1) Yes. You are building an engine to be as-new. Don't scrimp here. If you go with the old one, you will forever second guess that decision.
2) I don't know, but my Machinist does. (I have one that I trust.)
3) No need to worry about mismatching push rods. Just make sure both ends are nice a shiny, and that they are straight.
If you want to save some money, skip the hardened seats and go with stainless steel exhaust valves.
Carl
