he’s behaving like a normal bunny, bunnies chew and make messes all the time so he won’t “get better”. You can bunny-proof the room (shielding the plaster with cardboard or mesh) and be more careful about any object he might chew (headphones/phone chargers etc). If he’s bonded with the other guy I wouldn’t separate them (are they all neutered/spayed, btw?)

Like Muchelle said, this is what rabbits do. Especially if they are bored, have you tried offering him new things to chew? Wires are a big temptation for rabbits, and my rabbits are the reason I always put my headphones away now (in a few months rabbits taught me to pick up after myself, something my mam spent 2 decades trying to do!)
Is there a chance your sister would take the two that are already friends, and then you would keep the third new rabbit?
breaking up friends will probably result in both rabbits being very upset and unnecessarily stressed

Are the original two actually bonded properly and neutered/spayed? They all sound like normal bunnies. If you give one to your sister, make sure she knows all the time and work they take. They aren’t like dogs or cats

If you don’t want your headphones chewed, stop leaving them where white bunny can access them. Bunnies chew. It’s what they do. It’s YOUR responsibility to make sure they can’t get to anything that is dangerous/inappropriate.

Aww poor white bunny. Always feel sorry for those bunnies who are classed as an “annoyance”.I think you could have a fantastic bunny if you just allowed him to flourish in the right way. It’s like children, nobody likes a naughty child and they always get judged, but everyone/everything has something good and special in them. It’s just about finding ways for them to express themselves in ways they enjoy and that is safe and appropriate. Sounds like he likes chewing, so find him something safe to chew. White bunny doesn’t know he is doing wrong if he is getting provided with fresh new headphones for chewing and he shouldn’t be judged because his personality isn’t like the other bunnies.

It’s been said that taking care of house rabbits bears a lot of resemblances to taking care of two-year-old children, and I expect everyone here who has or has had toddlers knows what THAT’s like. So you have to take the same basic approach:

1) Don’t allow the buns access to anything they shouldn’t be chewing. Bunnyproof or create a special play area for them.
2) If you allow them free range or time out of their cage and playpen, keep them under supervision, make sure you know where they are at all times.
3) Give them lots of toys and suitable things to chew to reduce the temptation to be naughty. A bunny that’s running through a tunnel, whapping around a baby toy key ring or noshing on an empty cardboard tube stuffed with hay isn’t getting into mischief.
4) Never be harsh when scolding them. A loud, firm “No!” usually suffices. I’ve read that, sometimes, expressing your displeasure the same way a rabbit would, by thumping your foot or turning your back in a huff, also works.