hi junkyardferd, nice to meet you and glad to see you on here. Although I am unable to answer the first two questions. The third I remember seeing, so I dug up the old page I saw it on. (as I've been looking into the possibility of making a 393 stroker kit with a hydraulic roller conversion in it
Apparently there are a couple of companies that are making retro fit kits to make a non roller lifter engine into a roller lifter. I've seen advertised that Crane has this retro fit kit, you simply buy the kit and the matching cam and drop it in. It supposedly doesn't need any machining to fit in the block either.
I've also searched and Comp cams also offers this retrofit kit. The kit itself is a somewhat reasonable $54.65, but you have to buy the specific roller lifters which add an additional $230.25. Then you will need to find a small base circle cam, I'm sure if you talked to a representative, and told him what kind of lift, duration and other specifics you were looking for they could find the right cam for your project.
parts numbers for a quick search if you like are:
PART #851-16 - hydraulic roller lifter (it says 302 at the top, but if you look in the description you may choose the application from the list, in which
included is a 351W)
PART #31-1000 - hydraulic roller retro fit kit.
hope this is of some assistance for you.