1) Yes, you need to provide three copies of Schedule 1.
2) When all else fails - read the instructions. IMM0008 wants your spouse/common-law partner (not applicable for spousal sponsorships) and "all of your dependent children who are not already Canadian citizens or permanent residents" - that does not include your parents or sister(s). Your parents and siblings will be listed on Form 5406 -
Additional Family Info.
3) Not having any family has nothing to do with whether or not you submit a birth certificate. Your birth certificate is to verify your country of birth.