Swapping bridal party

Hi. Im a 30F and im getting married in October 2026. Almost immediately when we got engaged we wanted 3 of our friends as the MOH (TL) and 2 as bridesmaids (BR and LI) They seemed so happy to say yes. Fast forward a year and a half and they are too busy to go wedding dress shopping then all 3 go out to lunch together. I was invited to and went to LI's birthday party and all three stayed glued together and wouldnt really talk to me or dance or any thing. If one was doing something like ordering shots, they all were. They havent even talked to me or my fiance since november despite us reaching out to do lunch or other things. We are only invited out tovbig parties. My fear is at the bachelorette party-if they show up, they will just go off together. Im planning a day at the roller coasters and a spa night. I have a coworker who im very close with who i can ask to step up to the MOH position and i have ideas for other bridesmaids but how do i tell the first 3 that i want to demote them to guests instead? TL has been my fiances friend since middle school and her not making time for him is hurting him too. I dont want to be seen as a bridezilla or bitch and have them not show at all.