1. Yes, you need to know some more things but in particular not linking. I have no idea about linking or what to do when it fails with weird symbol errors. If you have a standard autotools, cmake or meson setup it might be as easy as just adding the packages to nativeBuildInputs and it works. The more custom stuff the project does the more you need to hold it hands.

3. For example here https://nixos.org/manual/nixpkgs/unstable/#chap-hooks

5. It is quite the opposite. If the typical build instructions are ./configure; make; make install then you might only need to specify the install directory to $out and you are done. Looking at ldd is also not usually required when compiling from source.