What's proper ettiquette for invitees to the rehearsal dinner? BP, OOT guests, parents/grandparents, other ceremony participants...who else? What if someone in the BP has a significant other? Are they invited and where would you cut it off? Would you just invite the SO if they're engaged/married, or would bf/gf count, too? Are you supposed to invited your aunts and uncles even if they're not in participating in the wedding and/or traveling in from OOT?
I don't want my guest list for the rehearsal to get out of hand, but I'm worried that my FMIL is going to want to invite all of FI's aunts, uncles, cousins, etc. because they were invited to FSIL'd rehearsal. I just feel if we did this we'd have to do the same for my side and my side is MUCH larger and it would be easily over 100 people, which in my opinion is way too much for a rehearsal dinner.