2 year sleep regression + sleep training 6 month old = send help!

My kids are 18 months apart and my daughter just hit the 2 year sleep regression hard. She turned two on the 15th.

No matter what time we put her to bed she will be up for hours, not upset or crying but playing, singing and kicking her feet against the side of her crib. She will wake up throughout the night for no apparent reason and then wake for good at an ungodly hour. She’s also fighting hard on the naps. Honestly, because she’s happy in there I wouldn’t much be bothered and we’d make up the lost sleep. The problem is, we have just transitioned my 6 month old son from our room to his crib.

We kept my daughter at the grandparents house the first night to see how he did, and honestly we thought he would be the problem and one waking her up. It’s turned out to the other way around. He’s a little tough to get down initially, but my daughter is the problem because she is waking him up constantly.

We’ve tried putting her down awhile after he’s gone to bed or at the same time. It doesn’t matter. We have sound machines in both their rooms but they are right beside one another with the adjoining wall the only place we could put the crib, so she’s kicking the wall, laughing super loud everything.

We’ve tried making sure she has nothing on her crib to play with. Doesn’t matter. She will carry on conversation with herself or play wit her pillow. We’ve tried ignoring her. Going in and hushing her. Scolding her. Nothing works.

Has anyone else dealt with this? I am at my wits end. My son is trying so hard but she’s making it impossible for him to sleep as he needs to. Tell me what to do? I am up all night long in terror of her waking him or trying to soothe him after he’s been started awake.