Tourist types 4 quick questions

1.I am an international student living in America. I do not have any bills in my name, I only have the lease agreement, will they accept that as proof of residency? I also have included my visa and i20 form from my school.

2.I have an E-ticket with a round trip and I have my hotel reservation- Do I still need to include a letter of why I am going to China and what I am doing there?

3.Does every single section on the application need to have N/A- Even for example where it lists whether you are filling it out for a minor.

4.On the Application when I type my email the box is not big enough-I am able to change the size of the font, how do I get round this?