Yes you can reroll the CTPE. You want to until you get at least a 180% damage Proc. It maxes at 200.
Cable especially if you plan on getting his uni. He does great in Corvus and Cull WBU. QS, Winter Soldier, Luna Snow, Gambit, Apocalypse, Anti-Man, Cap(only for PVE like WBU and ABX) are all ideal for CTPE. Cap is amazing with a Refinement for PVP.
Cable and QS are the best contenders and out of those two, Cable is better. Definitely give it to him. If you get another one, drop it on QS. Spidey does better with Destruction or Transcendence. Gambit will be over the crit damage cap with Energy.