First thing, where will the car be stored during stripping? Closed garage, carport, under a tarp?

1. Makes perfect sense, many do that.
2. Not silly at all either
3. I would probably choose a rust-proofing paint over primer, as primer is porous and moisture from the atmosphere soaks through and can cause rusting to start under the surface.
4. Shouldn't do, unless the area of overlap has not been properly cleaned before application.
5. Smooth surface. Primer does not need big scratch marks to adhere. A once over with progressive grades of sandpaper down to 240 grit will allow it to grip just fine. This should also help get rid of any ugly scratch marks from a scraper used on paint stripper or a wire wheel.

Personally, on my HZ which is in an enclosed garage, where I've stripped back, I have sprayed on WD40 and wiped away the excess. This has been protecting the bare metal from rusting for the last 15 months roughly with re-application every 6 months to make sure it does not wear off. The benefit of this is that it simply wipes off with prepsol as part of normal prep before painting.