Kingdom Hearts isn't canon to Final Fantasy VII, so since Tifa is an embodiment of light to contrast with Sephiroth being an embodiment of darkness, and Sephiroth has a black angel wing, then Tifa should have a pair of white angel wings. That's why I can picture Tifa with wings, but only in the Kingdom Hearts series, not in the Final Fantasy VII-related compilation or in Dissidia.

Of course, I had also mentioned earlier that it may be possible that the reason why Cloud stopped working for Hades was because Tifa might have intervened and told him about Hades' plans to use him to eliminate Hercules.

I am also very disappointed with the fact that Kingdom Hearts II is her ONLY APPEARANCE in the series so far, and that her outfit was pulled straight out of Advent Children. If I could, I would remake the original Kingdom Hearts for PS3 just to add Tifa in the Olympus Coliseum. Of course, I think her role should have been being a member of Leon's (Squall Leonhart) team in Traverse Town, where she would fight alongside her fellow Final Fantasy VII characters Aerith and Yuffie, but in order to put her in the first game without distorting the storyline too much, I would instead opt for having Tifa look for Cloud in the Coliseum, and then intervening to tell Cloud about Hades' plans.

I'd say that when they make Kingdom Hearts III, they should put Tifa in the game while wearing an outfit that is closer to her classic Final Fantasy VII outfit, but also having a few traits from Rinoa Heartilly's outfit in Final Fantasy VIII.