I'll just answer the first and last questions. Chicken, pretty darned cheap and high quality. I just recommend eating sufficient quantities of protein all the time, why make it complicated? If I'm in a rush then I'll have a protein shake or something.
Yes you can lose body fat and gain muscle at the same time, however you need to have your diet well under control and genetics starts to play a major role. As well as where you are in your progress, if you're overweight and under muscled yeah it's pretty easy. If you are a competitive bodybuilder (i.e. close to you limits) then going to be much harder.
"Go For Broke"
Fat Kine-230/24% @ 6'2"