Commenters asked about "kneeled" and "snuck" as past tense forms of the verbs.
These are just variants, and both are generally acceptable. (I say "snuck" all the time—perfectly good word, though children use it to make dirty limericks, so it's good not to let them use it, I guess!)
But notice the difference. "Snuck" is an old form, from old English, when past tense was usually signified by a change in the central vowel (sing/sang, sneak/snuck, kneel/knelt). Think about why that is useful—the change is so clear that there's no doubt when you say "sang" that you mean it happened in the past. (The –ed form is NOT as sonically clear, and notice how often we do without it—we often slip into present tense, just as I did there!) This was probably helpful when the language was still being formed and you wouldn't always know whether the person in the next county could understand your accent—they would notice a big vowel change like that. I have seen that even those irregular verbs that have a sort of –ed sometimes do it with the harder "t" along with a vowel change—KEPT and KNELT—again, the harder sound there would make it easier for a stranger to "hear" the past tense even if he didn't quite understand your accent otherwise.
(Did you know that the prefix y- before a t-ending past word was the way a lot of verbs made past participles? I think the only surviving such word is yclept, which means "(something) has been named or identified." and I only remember it because it's so weird.)
Irregular verbs (those that conjugate past and/or past participle with something other than -ed) are usually among the oldest verbs in the language, often called "strong verbs," perhaps because they are so "strong" they have resisted change and standardization for a thousand years. These are often the most important verbs, the ones in most common use—go and come and bring and is and have and get and forget and think and know and wake and sleep, and a couple dozen more. These are the ones children and non-native speakers have trouble with because they logically assume that you add –ed to make past tense: "I already goed to class."
Believe it or not, formation of past tense has profound linguistic and even philosophical effects, which I won't attempt to explain (have you ever noticed that the word "Chomsky" is a synonym for "difficult?"). But here's an article about Stephen Pinker's exploration of this past tense issue. (Warning-- .pdf file takes a while to load.)
So what happened? Well, there was the Norman conquest in 1066, after which, for a couple hundred years, Norman French became the language of court and the courts (which is why bailiffs still call out "Oyez, oyez," to open courts in a lot of states). While most Brits still clung to their native tongues (the Welsh and Scots, of course, are British but have their own languages even now), French words entered the English language, often existing right beside the old word, sometimes being seen as the "classier" term ("beef" is French; "cow" is English). Most "Latinate" words – 70% or so of our vocabulary, but more nouns than verbs!—came into English through French (a "romance" language—that is, based like Italian and Spanish on Latin), but our syntax (sentence structure mostly) is still Teutonic (Germanic), from a much earlier contribution/invasion.
Okay, as I recall, somewhere around 1400 was "The Great Vowel Shift," where the vowels (especially those in the middle of the word) became more long—shifting from the middle of the mouth more to the front – "ah" became "ay". This had something to do with social dislocations from the Black Plague, but really, linguistics class was a LONG time ago. So those same vowels which changed to mark tense were changing, and maybe the distinction between the forms was getting muddy. Anyway, after that, came the great trend towards standardization, imposed by dictionary writers and teachers and preachers too. This is when the –ed for past caught hold. (You'll see very few –ed past tense verbs in Chaucer, but lots in Shakespeare.) The London accent became the preferred accent, and the London way of word formation became pre-eminent. But English is a great and flexible language, and here we are, 400 years later, and "standard" still has little hold on us, does it? That's especially true with verbs, which are not as subject to change in context as nouns because, well, "the action of going" hasn't changed as much as "the method of going" (i.e., carriage to car to plane).
So we have in common English, and even accepted "standard" English, all sorts of irregular verbs. Most verbs went compliantly enough towards the standard, and we find that we walked and talked (though not "runned" or "speaked" or "sayed") without too much complaining. But sometimes, the attempt to standardize an old verb hasn't really worked, so that we have the new –ed version right along side the old version. Kneeled/knelt and sneaked/snuck are examples. There isn't a lot of reason, or for that matter rhyme, to which ends up preferred. For example, most of us would say dived, not dove, is preferred, but what about drived vs. drove? If your child said, "Daddy drived me to school," you'd probably make a gentle correction, "No, honey, Daddy DROVE you to school."
For some of these verbs, one form or the other won out, and for others of these verbs, both forms still exist as acceptable (though often one is preferred-- usually the -ed form, like "dived" rather than "dove"). This is happening right now, with plenty of debate, and it's actually a great example of where dictionaries are often trying to dictate the more logical way (-ed) and usage keeps the old way in action. (Some verbs actually went backwards—I read that "dived" is older than "dove," for example. But that's unusual.)
How do you know which is right? (And keep in mind that the British often have different preferences. I have never seen the word whilst used by a modern American writer, but the British use it instead of while.) Choose a good dictionary that identifies the preferred version in American or British English—that is, if you're American and writing for American audiences, use Websters, not the OED (and, uh, this is why we rebelled in 1776! Didn't you see that in the Declaration of Independence? "Wherefore they want us to say 'whilst,' we don't wanna?"). If you're British, use the OED, but often the OED comes down on the "descriptive" side of the description/prescription debate (do we just describe the major usages, or prescribe the "right" way to use the word?), and so often just trying to figure out dived vs. dove turns into a four-hour (but very pleasant) session in checking and cross-referencing different words and sources. I don't know about Aussies and Kiwis and Canadians and "post-colonials"—you tell me? Which dictionary do you use?
(One thing I love about watching BBC shows is the variety of accents—the British, for a much smaller nation, have many, many more accents than we do, and some, like the Glaswegian Scots, are just about incomprehensible to me. But then, I grew up in SW Virginia, and I stopped to get gas at a SE Virginia – swamp country—station, and couldn't understand a word of the man next to me. The cashier, a young local African-American woman, was bilingual—I mean, she could understand me and speak to me in my "dialect," and then turn to the white local man and start speaking that other language that I guess was how they speak English in the Dismal Swamp! Anyway, I could really get then why profound changes in sound to signify important things like positive and negative, past and present, would be helpful when communicating outside your own region.)
Now as for whether and when you can use the non-preferred term without the editor changing it... well, first, remember "house style" dictates, and if you want to dispute that, take it up with the publisher, not your poor editor, okay? Understand that, absent a house-style ruling, we will usually opt for whatever the dictionary we use specifies as "preferred," and really, how much of a fight do you want over "sneaked/snuck?" Save your ammo for when I change your character's deep dark secret from "he murdered his grandmother in cold blood" to "one evening, he didn't go by his grandmother's room to read the Bible to her as he always did, because he was exhausted from working 16 hours to earn enough to keep her in a decent nursing home and he fell asleep and slept through till morning, and poor Grandma had a heart attack in the middle of the night and he's always blamed himself even though she was 94 and had a heart condition."
Pick your battles, and I'd think "kneeled" vs. "knelt" isn't a hill you want to waste too much of your infantry on.
Okay, let's say you're a total sweetheart, a dream to edit, and you want to make this manuscript so clean the editor won't have to change a word? Ask the editor what dictionary the house uses, and work with that. (Edition will often matter here, because this "standardization" is still going on. In my childhood, "snuck" was perfectly acceptable, and it's actually still what I say if not write, but it's not the "preferred" form in current dictionaries.) BTW, the preferred form is listed first in the dictionary entry of the present tense word, so in the "sneak" entry, the past tense will be listed as "sneaked, also snuck." That indicates that "sneaked" is preferred.
Now, when the narrative is in character voice (deep POV) and in dialogue, use what the character would say. But if most of the narrative is in your voice, educated, intellectual, erudite, elegant, and then suddenly Their father drived the kids to school, well, don't tell me that one verb is "character voice". Character voice isn't just a word here and there. And if you are really in character voice, I'll know whether the words fit the voice. In fact, I'm likely to note, "Would he actually think the term erudite? Or would he think smart-assed?"