I485 and I131 filing questions

Hi, I am going to file I485 and I131 myself. Two questions for the filing:

1. Should I fill the I-864(Affidavit of Support)forms for my wife and my son seprately? One for my wife one for my son?

2. For I131 form, part I, item 3. What is the Class of Admission? How should I fill this?

Thanks for your help!