imo allowing Aeris(I know that's wrong but I'm used to it dammit) to be resurrected would take away the emotional impact of her death scene/cheapen it, so I hope she stays dead. Keep in mind I haven't played ANY of the spinoff games and I haven't seen Advent Children since it was first leaked in Japanese with subs in like 2004 I think, so I don't really remember its plot either. However, Aeris dying was a big part of FF7's story so I hope they don't cheapen the scene by allowing the player to resurrect her. Plus, since the game is based on reincarnation and that souls return to the planet via the lifestream(which is why using mako as energy is so fucked; they're using souls like petroleum), she never REALLY dies anyway and she helps you at the end of the game. I don't wanna spoil everything for people who haven't played the original so I'll leave it at that.
I've heard those rumors before but as far as the details go, I don't know what the original plans were. I like that they kept her "dead".
edit: After the mobile abominations that were the FFV-VI "remakes", I'd rather SE not touch those games ever again. VI has aged pretty damn well for a 1994 SNES game anyway, better than VII imo.