Only if the rim shape is otherwise identical, and the tyre ends up exactly matching the rim width. Maybe. Aero is much more complicated than that. You still get the ride and handling benefits of better tyre shape, so I'm not saying don't do it, but if you were actually bothered by aero you wouldn't be getting 24+ spoke metal rimmed wheels anyway.
Spokes:
Not really thought about them yet, might go bladed, might not. Either going to be Dt Swiss competition's or aerolites.
I'd always go the extra few quid and couple of ounces of Alpine III over Comps, and CX-Rays are at least as good as Aerolites and cheaper due to the DT hipster tax
Only if the rim shape is otherwise identical, and the tyre ends up exactly matching the rim width. Maybe. Aero is much more complicated than that. You still get the ride and handling benefits of better tyre shape, so I'm not saying don't do it, but if you were actually bothered by aero you wouldn't be getting 24+ spoke metal rimmed wheels anyway.
I'd always go the extra few quid and couple of ounces of Alpine III over Comps, and CX-Rays are at least as good as Aerolites and cheaper due to the DT hipster tax