Because of venue restrictions, we can only have our rehearsal on the Thursday before our Saturday wedding. FI's parents are planning on giving us a rehearsal dinner, which is very kind of them. However, they believe that the dinner should be the night before the wedding regardless of when the rehearsal is, because they don't think that we should even have a rehearsal at all; they're planning on it being just a "night before wedding dinner".
I know that we need to feed the people at the rehearsal afterwards, and I would have no problem doing so separately from the dinner that his parents are hosting, but I don't want to step on their toes, so to speak. I also don't want to try to demand that the dinner be on a certain day (especially since they are also planning on inviting OOT relatives who may not be in town on the Thursday). What should we do?