No problem just hit the thank button
I'd root and just leave it stock the rest of the way. With battery life it's always YMMV. The battery stats given in the setting menu don't tell you much so apps like wakelock detector or Greenify allow you to stop apps from "waking" the device all the time to either push notifications, sysnc, do whatever crap they do in the background. You could also get something called better battery stats, the app in on xda just google it, and let it run from full charge to dead and then take some screenshots of partial wake locks, how often CPU is in deep sleep etc and others can help sort some out.
Just root with Kingo as its easy and leave the custom rom's alone haha.
BTW how did you fix the brick form flashing a custom rom on MK2 ? I'm on the good MDL firmware so not sure how others fixed the MK2 brick