So you can fertilize like crazy and your plants will still be yellow and unhealthy. Here's kind of an odd question. I'm guessing smersh is talking about spontaneous combustion. Seriously, compost piles often heat up, sometimes to as hot as 150 degrees, and some people become worried that they might catch fire. The heat is a natural by-product of decomposition and a sign that your pile is working.
Any gasses escape as they are produced.
Again, if you have the right mix of stuff, it shouldn't smell at all. Paper is fine, though avoid glossy paper with colored ink. Some of those inks have heavy metals and other unwanted ingredients. I have friends who shred brown shopping bags and even cardboard boxes and compost them. Tea bags, coffee filters, all that stuff can go in.