Brendan, thanks for the tips.
So it seems Person A's Aeroplan can transfer to Person B's US acct, provided A & B's accts are not already linked to 2 different points.com accounts.
Amex->Aeroplan and Points.com transfers seem instant, so I'll find the award seats, place them on 3-day hold and then initiate the transfers. Will let you all know if it goes through without a hitch.