For the dissimilar metal thing, google galvanic corrosion or stuff like that. It is a big problem on boats, read about the zincs ( sacrificial anodes? ) that are hung on the bottom of boats.

Calling the fuses copper is probably a misnomer, they are probably a copper alloy. The contacts in the fuse box are probably a harder copper alloy or they may be plated.

Almost all metals react to some degree, copper, aluminum and silver included. They call it by different names under different conditions and circumstances, annodization, tarnish, corrosion, rust, etc.

Pennies are not made of solid copper after 1982. Put a copper penny on top of your battery and it will corrode but the battery terminals will not. I have meant to find the explanation for this for years and have never done it.