We have a family bedroom, but my two older kids sleep in a double bed together. I put them all to bed at the same time, and I stay in the room with them until they're asleep, so there are no shenanigans!
They don't really wake each other or bother each other. DS1 was sick and vomiting over the weekend, and even that didn't wake DD. I think they just get used to being together. DD has woken a few times, accusing DS1 of sleeping on her side of the bed and snuggling with her, but it's usually her encroaching on him and sleeping on him, lol! That has only happened a few times when they first starter co sleeping though, now they're used to being together.