I have two brothers, both married. We weren't planning on inviting either of their in-laws, but we are somewhat close to my one brother's brother & sister-in-law. I had initially wanted to invite them but asked my brother about it. He said under no circumstances does he want his MIL at the wedding and jokingly said he wouldn't attend. Concerned that if we invite the brother and not his mom that she would find out and be upset, we just decided to not invite any of them.
My SIL is now planning my bachelorette party and knows I won't have a lot of friends attending because they are all out of town. She asked my mom if she should invite her SIL because she knows we get along really well. Obviously we can't invite her to the pre-wedding parties without inviting her to the wedding.
Is it in poor taste to only invite the B/SIL and not the F/MIL? I know that everyone would prefer it because she's overbearing but I don't want there to be a problem.