the answers on the pistol are to my knowledge with a few 80% ar's under my belt, never done a pistol though.
1. not really, it depends on what parts and where you source them from, cheap just don't cut it
2. drill press, dremel, few files and hand tools. I do know of several polymer 80's done with just a dremel and a few files
3. build it as you wish adding the parts you feel perform the best
4. up to you to decide, the fun is in the build
5. the old reliable 1911 is out there as well as the glock, maybe others these ar the ones I have seen.