I can't answer all of your questions, as I'm new to the AVP platform myself, but I'll share what I do know.
The telltale battery is located on the backplane. It should be zip tied up and resembles an old cordless phone battery pack. They're rechargeable and sometimes will charge with the machine on if they're not totally dead. I just placed an order for some for a few machines I just got in.
The license tilt has to do with your date/time not being set. Had the same problem when my machine thought it was 2004.
In order to reset everything, you'll need to do a clear and re-set up your machine. I'm not the one to go over this procedure with you because I've only done it twice and was walked through it step by step over the phone with a knowledgeable member on here.
I do know that you will need a Diagnostic Key along with eKey7 to do a wipe and set up. And never insert or remove the Diagnostic Key with power on the machine. It will fry it.
That's a out all I can tell you. I'm sure it won't be long before one of the experts offers up some better advice.
Good luck.
Curtis ash100