Family forced into wedding!

Has anyone else had family drama/been forced to have someone in your wedding you didn't want!?

My cousins on my mom's brothers side and I are not that close. His children are underage and at the time of choosing people, was not even an adult yet. His son and I really don't talk and his daughter has an anxiety issue talking to certain people, me and my family is part of those she doesn't not speak too (physically). So we never really talk either. They just stay with their friends or in their rooms when the family gets together which I understand is age as well, point being we aren't close. So my uncle got really upset/mad that his kids (daughter specifically) wasn't in our wedding. I already had picked my 5 bridesmaids and didn't want any more, FH didn't want his boy in his party and we had flower girls, ring bearers, etc! He pretty much said he wouldn't attend if his kids (again, daughter specifically) wasn't part of the wedding. For me this was ridiculous and I don't deal with that kind of selfishness especially when he is not contributing to anything and it's my day not his kids? In any case I still qanted them to attend and tried to think of ways to incorporate them. His daughter does colorguard so I asked her if she wanted to do a routine during maybe cocktail hour or so and she was excited and I an now too. His son though I' still not sure. He acts like a 10 year old so I'm not sure if he can be mature and seat anyone, I wanted him to be our DIY DJ but we aren't doing that anymore. We have two ring bearers already so the little ones feelings werent hurt. When it gets closer I am going to try to habe a mature conversation with him and see if he even wants to be a part of it. My uncle is now happy (being that his daughter will have the spotlight).

I'd like to know who else has dealt with finding spots or compromising with family members wishes! Also, if you have suggestions for me with him (he is now 19)..?