Yes
No, Fiero seats are pretty special to fit in where they are. I recomend you repair your old with parts from the fiero store.
yes
Yes
78-87 Monte Carlo is a G-Body GM car that is smaller than a 77-90 Caprice which is a B-Body GM car. The seats in a Monte Carlo will fit in a Caprice, but they may not look quite right. You will need to do bolt location modifications. I would not recommend trying to use a bench seat from a Monte in a Caprice. It is not wide enough.
Yes
Yes
Not without seriously extensive (and expensive) modification
There is no such thing as a 2010 Monte Carlo, so the answer would be no
Speakers for 2004 monte carlo
NO. Not even close.
yes