A) helical mounts are available for LF lenses on eBay for about $140 or so --- many will have the right numbers on them if you tell the seller what lens it's for. search for "helical focus"

B)it is not difficult to find the focus for a lens and then mount it correctly in a helical mount.

C) a lens set for infinity will be in focus from the front focus point out to infinity-- a lens I have built several panoramic cameras with a Rodenstock 90mm wide angle lens--- it will be in focus a f22 from about 11 ft from the camera all the way to infinity in the distance. The entire camera is about 6 inches deep, and the lens just under 4 inches from the film.

D) I have yet to find a 35mm focus mechanism that I can mount a LF lens in -- I have seen it done with MF lens mechanisms, but why screw up a lens.

E)Any lens that will cover 4x5 with no movements is suitable for the project.