'96 AWD and studs ?

I just bought a '96 AWD Astro w 130k miles this weekend and need a little info on the AWD system.

Short story:
The outer edges of the two front all season tires are balding, one is to the cords (not an alignment issue). Which I believe to be worn idler arms. Van came with 3 new extra studded tires, cause the owner did not know where the fourth one went.

My question is since it will not pass the safety inspection with the current front tires is it safe to put two of the studded tires on to pass inspection and long enough to get it smogged, insured, registered, and have 4 new tires put on (two weeks tops)? We have a big storm coming in Wed. and the wife will be driving the van.

If it is safe should they be placed on the front or rear? I know that the '99 and later models are RWD until slippange and then the fronts engage, but what about the '96? Is it 50/50, 60/40 full-time AWD or what?

Forgive my ignorance as my previous vehicles have been FWD or 4WD with a transfer case and manual locking hubs. My current daily drive is FWD with a VLSD so I do undertand the concept of viscous differentials.

Got an owners manual should describe the design of the transfer case, I believe it is 60/40, I'd put the studs in the rr