1) Yep, dichlor will provide chlorine to keep the pool clean while building CYA.
2) Maybe dissolve it in a bucket first. Make sure it get dissolved.
3) The Kem Tek product on the Super Simple recipe page or the Pool Brand from Sam's Club are usually fairly priced.
4) About the same as dichlor. As you test daily you'll learn to adjust the dosage to what your pool needs.