3. I think the way Newegg handles it is to allow only one billing address to be stored, but you can always enter a different billing address when you check out, you just can't save it as a different one. As far as moving, you can edit the billing address, just not have more than one. I guess it doesn't matter either way since the code to have multiples will be there. I'm just assuming that there is a good reason that Newegg only allows one billing address.

4. If you wanted to store the store's addresses (ok that's confusing, let's call it store the business's address) you could use the administrator's account. Since you will be able to store multiple addresses and the administer will always be user 1 (I think it works that way), this shouldn't be a problem. Do you think that will work?