FI and I are having a more relaxed, casual feel to our wedding. Our rehearsal dinner is going to be in a private room in our favorite restaurant. FMIL and FSMIL (is that how we abbreviate future-step-mother-in-law?) are splitting the cost evenly, something that they offered to do. FMIL is on a very limited budget while FSMIL has a bit more money to throw around. FMIL isn't really a wedding person. FSMIL loves weddings and all things related to them. Given FMIL's financial constraints, we agreed that we would only invite immediate family and bridal party with SOs to the rehearsal dinner. The total guest list is maybe 30 people all told, so it's a smallish group.
Here's my dilemma. FSMIL has taken over planning the whole thing, which I am fine with to a certain extent since she is paying for half of it. However, at this point, I feel like she's trying to make it into a wedding reception in its own right. We're talking a guest book, favors, etc. for the rehearsal dinner - we're having all that at the wedding the next day! To me it seems very awkward and odd, and makes me a little uncomfortable for some reason. I should also add that I barely know FSMIL, as we've only met once (they turn down every invitation we give them to do something together, come visit, etc.). Her plans also include things like putting awkward baby pictures all over the room (I know this is a tradition for a lot of people at RDs, but I was a very awkward and chubby kid and I am not comfortable having those pictures on display). FMIL wants us to have what we (FI and I) picture - small, casual, relaxed, with no photos, guest book, etc. However, she's not willing to stand up to FSMIL since there is some history there and she's afraid that if she puts her foot down, FSMIL will go running to FFIL, who will call up FI and yell at him (it's happened in the past).
How do we handle this? They are paying equal halves, and FMIL's vision coincides with our vision while FSMIL's does not. Is this a case when it would be appropriate for FI to talk with FSMIL and try to rein in the plans? I know since we aren't paying for the RD ourselves that we're not supposed to have a say unless asked, but it's driving me a little bonkers at this point. I'm afraid I'm going to be sitting there for a couple hours just cringing while people comment on my horrible baby pictures and side-eye each other at the mini-reception feel to the event. Do I smile and bear it or does FI say something?