18 inch
No. You'd have to buy an adapter
Yes you can fit 20" rims on you 1979 cutlass, if you wanted to you could fit 22" rims with low profile tires with the stock springs.
Yes, a 1979 Firebird tail light will fit a 1979 Trans Am. There are also restoration services if you have the tail lights and they just need to be repaired.
Yes
YES.
Some parts will fit, depends specifically on what parts you're referring to
22 rims will not fit any ford escort.
no will not fit
Check the Firebird and Camaro seats.
Yes
no. but it will fit on a garbage truck