Pokemon Black Version 2

Hi guys, the gamefaq boards have been so helpful to me so far in my pokemon career i need some questions answered about EV training that i cannot seem to get the answer to after reading multiple faqs about it.

Can you gain EV points from trainer battles? - Yes

Can you EV train a pokemon what is not at level 1? Example i have pokemon i use for battle subway that are level 50 can i still EV train them? - Yes you can Ev train even at level 100

Also for the level 50 pokemon that i will EV train after I've EV trained them and take them back into battle subway will the new EV point enriched stats register for the battle subway which locks the level of my poke's at 50? - Yes, any EV's you gain are registered after the battle you gain them in.

Does the stat increases of the EV training happen after a level up? Example i kill 30 golurks or whatever to gain the ev points to increase attack, do i have to level up my poke and then his attack stat will increase by 20 or whatever after the level up? - Your stat will never increase that much unless you EV train at like lv99. But all EV's are given after the battle, which means if you earnt 4 or more EV's in a battle the stat would increase by 1 point visibly if you were at lv 100. But nonetheless the EV's would be still counting towards points at any level.