If there is; I'm really sick of only getting glams from the male FF characters-- aside from Lightning in the Mog Station; but she's not even a well-written character. (What character in a single FF has been though, recently?) but honestly? I'd rather have had Vanille's Glam or Fangs glam from FF-XIII.
If there is an FF7 cross-over event, there needs to be a Tifa & Aerith Glam including their hairstyles. (I'd also like to see Vincent/Sephiroth/Yuffie. etc.)
Then, maybe Yoshi will consider doing an ff V, VI or VIII cross-over event? With Rinoa/Edea/Selphie/Quistis/Zell & Irvine's Glamours. Heck, maybe another chance at grabbing a car mount- the Red Car Squall drives during the Sorceress Parade? Imagine Ultimecia in FFXIV?
And as for FF VI; just imagine Kekfa actually getting the acknowledgement he deserves- Him breaking out of Sigmascape & Terra enters your world. It would be amazing.
There are better written stories than FF7 that could use a cross-over & would just be more icing on the cake!

So, all in all, if there is an FF7 cross-over event, let's hope Yoshi doesn't snub the female characters in obtaining their glamours or any glamours at all. Yes, glamours make a game just as rewarding as well as a good story.
I think it would be great to see Red-XIII again. He was my absolute favorite character from VII