1) Look at the seat tube's bolt clamp, does it look like closed-in and not parallel? If so wrap a rag on a suitable sized flat screwdriver and force the clamp to open a bit while u insert the post.
2) All I have to say is, the gummy hood is pliable, don't be afraid to stretch it.
3) The pedals are NOT INTERCHANGEAGLE! Be sure which side is which. The right side is normal threaded (clockwise to tighten) while the left side is reversed threaded (cc to tighten).
4) Don't remember but I believe so.
5) Comeon man, any restoration, major maintenance, give it a new chain. $15 bux?
If u give up, wanna sell that frame to me?

P.M. me with a pix, history and $.