I just ordered a Shiny. can't wait!
I was going to suggest Echo and Fives if you were putting him with the 501st as you suggested above. Of course a few drawbacks with that are they are phase 1 only (if you prefer phase 2), they cost more (but are better value on a per head basis), they aren't on double rewards and oh yeah, you already ordered the shiny
Congrats, you won't be disappointed. Now lets see how long until you tell us you've grabbed a second!