What would you do?

Sorry this is a long read, I didn't go into much detail to keep it as short as possible. So my MIL hasn't been around since her and my husband got in a fight 2 months ago. They've since made up but she still hasn't bothered to visit. During their fight she talked shit about my family and me. (Not the first time she has talked about me or disrespected me.) That was the end game for me though. You can disrespect me but don't disrespect my family when all they've done is love, support and welcome my husband as if he was always part of the family. We've been married for 3 years, it's been non stop disrespect from her and her mother. I always bit my tongue until last year when they tried undermining my parenting. However, I showed face until she talked about my family. Well since then she has missed our son's 2nd birthday and the birth/visiting our daughter. Baby girl will be 4 weeks next week and she's never even called/texted to ask to visit. So my problem is baptism. We're having it the first weekend in December. It's at my parents house and originally we were going to ask BIL to be God Father. (The reception is going to be at my parents because we couldn't fit everyone at my house.) I don't want MIL thinking she can talk shit about my family and be welcomed in their home 3 months later. My BIL hasn't bothered to text or call either about new baby. So what would you all do? How would you handle this? I feel like if I just sweep this under the rug then I'm letting my family down. I hate to put my husband in the middle as well. Help please and thank you.

P.S. We don't go to her house because it is filthy, too many animals that are not flea treated, computer wires everywhere because my younger sibling in laws are homeschooled. The family room has floor boards that aren't attached properly so they move under your feet, so my husband and I don't find it to be a good place for our kids.