Are wheels interchangable

I think so

Unless somebody has some crazy offsets, yes. I'd suggest checking the front wheels through full motion but it should be fine.

Not really.
Theres a substantial difference in offset - 80 series wheels have more backspacing than 60 series.
But.... the 60series split rims go well on the 80series - the track gets widened. But 80series wheels don't go well on 60series - likely to foul on the inside.

And all 60series and up to late '92 80series can take the 15 inch wheels. But later 80series need 16inch wheels.