The rear motor is reverse rotation.
If the motors have adjustable timing rotate the endbell 180 deg for the rear motor.
If the motors are at zero deg you can just reverse the polarity.
I usually run 17T or 19T motors, just depends how fast you want to go, those motors I feel give decent speed, but not too fast that you will break very often.
As for esc, multiply the single motor turn rating by 2 for the dual motor rating (for parallel wiring).
Eg:Esc rated for one 10T motor is good for 2 20T motors in parallel
Only a few esc's have a good bec rating for strong servo's, so you will probably want to run an external bec like Castle Creations
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXSWL3&P=7
I usually run a Hitech HG645MG servo
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXUZ89&P=ML
A good Esc thats still avail is the Castle Mamba Max
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXUTA3&P=ML
Tha Hammer Pro should be fine with dual motors,
I believe it had no single motor limit, but it would be best to contact Novak about dual motor limits(probably around 15T motors)
And easy and good mod is to 4 link the suspension, just buy a Esp Chassis brace and either make some links or contact Brett @ CPE and tell him what you want as far as wheelbase.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXF283&P=ML
http://www.crawfordperformanceengineering.com/aluminum-links-c-1_21.html?osCsid=907fe64536e064d28b018c2ce88f46eb
You will probably want to change the steering to an axle mounted servo, which are easy to make, or Brett can sell you a setup for that too.