I like my FSIL, and we get along, but I just don't know her that well. I was trying to keep the wedding party small (like 3 BMs) and ended up with 6 GMs, so I didn't ask her to be one. For a while I felt guilty, until one of my cousins realized I wasn't going to ask her to be a BM and her response was "Thank God! I finally get to go to a wedding and just hang out with no responsibilities!"
I was considering making FSIL an usher or something until I heard that comment from my cousin. I thought maybe FI's sister would enjoy the wedding more if she just gets to hang out and not worry about anything? But then I go back and forth, because I want to include her and make her feel important, since she is FI's only sister.
Would it be rude to ask her to be an usher? Do people even like being ushers?