I would not purchase from card pool, there are other company that have better customer relatshion and better method to obtain your cards

Yes

Yes

Yes, as many as you want at brick and mortar stores. Web based sales such as Home Depot will limit it to 10 cards, You should check with the web site before buying too many for a single purchase. I think there was one site that limited me to 3 cards per purchase.

Yes. A groupon or other promotion is usually limited to 1. But giftcards in multiple should be no problem.

Yes, I haven't had any trouble doing that.

Yes, you can