Hi.
The temperature is because of your hardware real working to compute mobile blockchain.
I heard that ETN doesn't actually do blockchain job so it is no wonder that they don't get temperature rise.
Just imagine playing mobile game and your phone heats up, it's the same.

And the pending balance needs some time to be proofed by miners. This is the same way that happens in Ethereum and Bitcoin. This is called PoW.

Background mode is not supported as your phone requires to put focus on blockchain computing. It is an intensive labor.

You can ask more question to Support@mibcoin.io

Kind Regards.