When you go to purchase AP it gives pick your paypall account or credit card. The card does say specifically cannot be used for pre-authorized payments or reaccuring. Which i think is kinda where the paypall would come in. The bummer of using to buy actual cards is the lack of supply.
I was actually going to suggest this but if the AP cards are not available in your area, the suggestion become moot. You are correct in that you cannot
use a pre-paid visa card with a pay-pal account. When friends/family ask me about gift cards I always tell them to get me the Aeria card
If you limit your AP purchases to a single CC, maybe 2 and space out the purchases by a couple of days, I don't think you would lock up the account, but I do think that risk is there if you use 3 or more, especially for large amounts. If that happened you could go through the appeal process but as you point out, not being able to participate would be a concern.
I'm not that familiar with the pre-paid cards but it occurs to me that one other thing you might be able to try is seeing if you can cash them in at a bank. If you could, then you could take the entire amount from all cards and put it on a single pre-paid card.