Will 74 Satellite doors fit and are the same as 71-72 doors? How about qtr panels?

Nope 2 different doors. 71-2 are one type and 73-4 are another. Qtrs. are 71 only cause of the rear marker but could fit a 72 and vice versa. 73-4 are their own qtrs.

How about the frame rails? Would they all be the same for 71 thru 74? How about trunk floor and whole front and rear floor boards? Inner fenders?

Inner fenders are 71-2 only 73-4 has completely different inner fenders even from small block to big block on the passenger side.
Trunk floor is the same 71-3, 74 is it's own raised trunk floor.
Front frame rails are 71-2 only as the 73-4 front rails are different and has a completely different suspension where the upper control arms mount to the k-member not the frame rails. The front floors and rear floors can be used. I believe the rear rails are the same.
Keeping in mind while some of these parts will fit there are some differences in appearances and body plug sizes in the panels but they fit.

Also 4-dr trunk pan is about 1" longer than 2-dr.
71-4 rear frames are the same for both 2 and 4 door.
I have found 3 different 72 front floor pans. Just minor differences and all will fit both 2 and 4 door.