Why would you cab flash again? V8 looks like it just changed some of the software on the phone (no source released for it yet, so unlikely that they changed anything major).
Just re-run the pwnage tool to get root and CWM then carry on as normal.
I cab flashed V8 just to make sure this worked and to obtain the files. No issued between V8 and the pwnage tool.
Does what? Monitor battery?
Try
https://play.google.com/store/apps/details?id=com.rootuninstaller.bstats I've used it before... seems decent.
If you have a terminal emulator installed (any why wouldn't you?). Just open it and type su. If the prompt changes to # you still have root. If it doesn't you've likely taken an OTA and lost your root and unlocked boot.