both have good lipos and chargers at low prices.
the volcano epx pro has a low center of gravity. it will not pull wheelies easy, not on nimh or lipo. it just launches hard with all 4 wheels ripping at the ground
not sure on your 3rd question.
the ESC and motor will run fine on 2s lipo. no need for fans. that said, a heat sink on the motor isnt a bad idea. heatsinks and fans cost alot less than new ESCs or motors!
the novatech ESC has plenty of punch. it actually can handle 3s lipo. it doesnt have any programable settings, but its very easy to use.
the volcano handles dirt/grass with ease.
i have actually run a volcano epx pro with a traxxas VXL brushless system on 3s lipo. it was pretty nuts. the stock setup with a 2s lipo is a good match. good power and speed.