I can't answer all of your questions, but I will answer one.
The batteries need to be dead before you recharge them, I say this from experience with the same battery. I have one that I did recharge even when it was not needed and now the battery life is almost half of all my other ego batt.
I have been told you can wash the material that's in the cartomizers, but I don't know how, so I await that answer.