I know what you're saying, kinda, but you do see faces/illusions in games sometimes because a pattern is a pattern whether it's computer generated, human generated or natural.

A while ago I remember spotting what looked like faces and even a figure that looked like Quina from FFIX, in Everquest. However they were just random patterns in stone walls, and as they'd joined some textures with symmetry that also enhanced some of the illusions. (At the time everyone told me I was barking mad lol). So it does happen.

Your mockup looks more like Squall from FFVIII FF's answer to the Emo has come back to haunt us hehe

The thing about her death being based on Sakaguchi's mother was an old rumour that keeps coming back. It's been debunked on these forums a good few times now His mother actually died in 1988, long before FFVII's development, and it's been stated by him somewhere that Aerith's death didn't come from that (use the search thingy to find out more)

I find it most likely that they changed when she was going to die, and originally there would've been some game content within the church. They then didn't quite take her sprite out properly. They certainly didn't have AC in mind back then as at the time it hadn't even been thought of.

However, IIRC in the finale of AC you get to see her tending to the flowers with the 2 kids (from the game glitch) before she stands up and looks at Cloud? Maybe not, I can't remember... will have to re-watch sometime. Again, I think this is most likely a nod to their fans who remember the glitch from the game.

P.S. You have way too much time on your hands