I would personally try to find some more cooperative wiring, but here is what I can tell you.
Your 97 passat engine wiring will hook up to the 90 G60 interior without a problem. So will the 94 gauge cluster wiring.
You should be able to use your 90 MAF stalks as well, they are going to be run through the fusebox and as long as the gauge cluster was set up for it should work.
As for the extra plugs from the cluster, if they are on the fusebox end some of them will probably not be used (this is the case if you use an A3 cluster in older A2 wiring) Now they may be part of the MAF system and you might want to trace them out and some wiring may be need to have everything functioning.
Lastly I am going to say that most likely you will need to make the D8 to E2 jump. A2 CE2 fuseboxes were not wired to send extra power to the gauge cluster and that is what that jump allows. Since you are adding a later style cluster I would assume you will need it. If you dont want to do it right away, just plug in the cluster and see if you get all of the gauges working.. if not you need the jump.
I know that those were not 100% answers but I usually try to stick to matched wiring where possible. Hope it helps