Simple answer is "yes". 1990-1994 were very similar cars. I don't think there was any change in A/C during those years. And being that both are 3.1 engines...i'd bet money they interchange.
No, the compressors and mounting points are different on the 95 Lumina
yes if its the not the DOHC from the Lumina Z34
1996 Chevy Lumina 3.4
Yes
Yes
No.
One way would be to remove the window panel from the enclosure and build a frame to fit the air conditioner tightly into the hole.
Yes
Yes
Yes
Yes
Lack of gas. If you go to Kwik-Fit, they can reboost it for £45. Hope this helps :) It cause the air conditioner to get hot because when cool air gets in hot air gets out.This is how its hot.It is also how it cools your house.