A.L.
You daughter sounds level headed and if she doesn't like the MAIN attraction movie and food and can't even enjoy the food due to allergies.. well, I don't think she should go.... Also, can you explain to the M. pointblank (leave no room for discussion) my D isn't going to attend due to being a little weary of the food choices and possibly bringing on an allergic attack.. which actually, for a kid, let alone adult can be a big fear..
As for the other situation.... save that for a different time. .first tell her about the party... she may take offense and think the two are related when in fact they are not....
cross one bridge at a time...