The same name is what counts, the B.Net accounts mean nothing.

If you want to transfer toons, there is a 30 day wait, from the time you join a B.Net account.
Well, no wait between accounts on the same B.Net email, so that is a consideration.
Also, you cannot go with more then 8 games on one B.Net email.

If you want to level some of your existing accounts.
I'd go with (A, B, C) as existing accounts.
And RAF them like this:
A (booster, no links).
B -- D
C -- E
Then group A-E together and boost away.

When you're done, BC have boosted toons.
And DE grant levels to BC.

And you can then do the same with two more existing accounts.
And two more of the vanilla wow accounts.

I'm basically going to do this, for 4x Worgen in Cataclysm.