Since I hadn't experience enough failure early in life, I think most of my characters were based on self. Nowadays, I've gotten a little better at separating my life from the book.
Tricky. I think writing does naturally come at a loss of time spent with others. I've often considered giving up my guitar hobby, but I think a balance of interests can be achieved.
Sure! Give yourself the time and space you need to unwind after a long period of writing or research. I like to listen to music when I'm feeling exhausted.