I'm going to be doing the D16y8 swap soon, which is almost identical to the z6 engine, but here's what I've learned so far:
Yep, you should be able to use all that stuff... P28 ECU, and you'll have to wire up for OBD1. Everything else should work, you'll need to get a VTEC controller or an RPM activated switch for the VTEC.
As far as the tranny goes, I would stick with a 4G Si tranny or a ZC tranny with an Si final drive.
I would also recommend purchasing a wiring harness from dropshop (
www.thedropshop.tv). They cost $150 I think, but I hear it's very worthwhile, unless you wanna spend all your time cutting and splicing wiring...