i need the key to get back into midgar. the guy in the outskirts said he lost it at an excavation site, which would be bone village, right? well, where in bone village?! I've honestly looked about 30 times everywhere, but found nothing but potions. so could someone please help out?

You could just set diggers looking for the rarest item, but it's easier just to go to the destroyed plane on the dinosaur's skull.
There is an excavtor near the bottom of the screen. (He might disappear if you go in to "dig mode", I can't remember.) Next to him is a tiny piece of metal sticking out of the ground. Position yourself underneath it and press up so that your character is looking forward, then dig.

Back in Midgar, you can get Tifa's ultimate weapon in sector 6, (small hut with a computer which you couldn't enter earlier,) or buy a stupidly expensive "sneak glove" from the bloke who sold the batteries.