Capt ,
Not much of a issue really
.
The 2212/10 at 1400 KV should do the trick. Regularly do 2 motor set ups like the twin star and MOSS 4 x now a days .
Just finished a 4 motor set up today with 4 ESC's and used one of the ESC's to power the receiver
I would go with a 11.1V 5000 mah battery to power 3 motors as the RCG thread clearly states that heavy battery would do well as it would give you better flying time and add nose weight instead of adding lead to balance CG.
Solder . the +ve's of the three ESC's to the Positive of the Dean Connector and the - ve's of the esc's to the negative of the Dean .
As for the receiver connection you could use 2 nos Y connectors to connect the Three ESC out puts to the throttle channel of the receiver and cut off the + ve of one side of the Y that plugs to the receiver .
2 side motors will go into a Y and the out put of that Y will plug into the second Y with the third motor .
Quite straight forward actually .
Eg , I power 4 Motors with ESC's but the +ve for 3 of them are disconnected only 1 ESC has the three leads pluging into the receiver.
Come over and I can rig it up and demonstrate it to you no problem.
Sai