Scrub radius is not an issue since you are not changing the offset at all.
But AJ's idea about stacking some washers on the studs, then mounting the wheel is a good idea. Measure the clearance, then subtract the height of the washer stack. Even easier than my idea.
I don't think the factory Small Bolt Pattern rally wheel came in any size other than 14 x 5.5 — all those wider ones are either LBP or aftermarket. On another thread, someone was complaining that his factory trim rings didn't work on an aftermarket rally wheel. I can see how this would happen with different wheel widths and backspacing — that also affects the "frontspacing" — the depth the trim ring set into. So I'd say there are no guarantees there. But the center caps should fit — why would they be any different?
Oh, I just saw where someone posted a Facebook marketplace ad for a set of factory rally wheels ... don't know if you're on FB. The only contact info is through FB or I'd post it.