If you plan on multiboxing with 2+ accounts, I strongly recommend that they all be your accounts with your identical name, address, contact info, etc...

You will come under scrutiny at some point by a GM, and it's much better for all the accounts to really be yours 100%. If you are just powerleveling some friends, it's not a big deal, but the first time your team sees a capitol city or PvP, you're going to get reported.