Multiple rebels is going off into a different thread: Why a werewolf would want to rebel in the first place. The way you describe it, it's like you expect multiple werewolves to rebel just for the sake of rebellion. That's not a smart thing to do: Normal people don't live their lives thinking primarily on what would be more fun to watch at the movies.
Yes, multiple werewolves may rebel, but presumably not until
after they have a damn good reason. Just the same, they would also need a damn good reason for the rest of the pack to let them train in their gestalt form and become even more dangerous than they already are.
Regarding secrecy, remember what I said about a person's natural tendency to wonder and wander? The Pack would also want to know why he's being so secretive and/or why he's distancing himself from the rest of them too. Don't forget, if one werewolf is exposed, it could trigger a witch hunt that could wipe out the entire pack, so it's in everyone's best interest to know what all their other packmates are up to. Someone would want to know what he's hiding and eventually figure it out, and then he would have to explain why he was secretly teaching himself a form of martial arts while in gestalt form.
So lets go over the reasons you mentioned:
Boredom? What, being able to do this
isn't exciting enough? And a desire to be better than Chuck Norris doesn't answer the question; it just raises another: Why do you want to be better than Chuck Norris? Power just for the sake of having power is no excuse; the pack would regret ever turning him in the first place.
War? On who? If it's a legitimate threat to the pack, that would be one thing, but no pack with half a brain among the lot of them would ever support a werewolf's desire to use his gestalt form to settle a personal grudge.
A desire to be independent and/or a shut-in? Again, he'd need to explain why. If it was for something personal, a dispute among pack members maybe or a disagreement in the way the pack is being handled, that's one thing. The pack would have to settle that dispute, hear his ideas and/or explain why things are the way they are. If he was just naturally anti-social, he wouldn't be trusted as a werewolf. No werewolf should ever be left completely alone because of the ripple effect that I mentioned earlier.
And lay off the insults. Just because I don't automatically conform to your will doesn't mean there's something wrong with me, OK? I'm trying to be respectful, I would appreciate it if you could do the same.