Not really sure on the voucher but it would make sense that they would accept that for parking.
When you do show your AP to park, you don't need your license, just show them the back of the AP where the expiration is.
We went last August with just the confirmation from the internet that we were buying Annual passes to be picked up at Disney and they let us through without paying.
I was so disapointed that our seasonal AP does not cover parking. They are still LOTS of money, LOTS of blackouts and no free parking? I was really not happy