1. Warm is ok too hot to touch? Nope, not good
2. You will download it via settings>software update when it becomes available
3. Not sure whats going on there but with the other issue (heat) along with this.... a new phone might be the wisest thing. At least that is my opinion but others might have better advice for you
Welcome Aboard by the way
Note: My phone gets warm but its nothing major. Its not even something I really notice.
Idle mine is @ 34 celsius
after a 10 min call it was @ 39-40