On Relatives
1. I have a close blood relationship but she is my cousin and she is a citizen of Canada. Can I include her as a sister?
2. If so, in the required documents...they have asked for proof of relationship and proof of residency. How do I show the proof of relationship? Also will any monthly bill do?
You can not list your cousin as your sister because she isn't. You can not claim points for a cousin in Canada, only direct line and brother, sister, aunt, uncle, nephew, niece, see http://www.cic.gc.ca/english/immigrate/skilled/factor-adaptability.asp
Personal History
1. There are only 5 rows and I have done a lot of things in parallel. How do I accomodate all of them in here? Or do I group them. I can't delete any because there are at significant time periods.
Type up your own list and in the last line of the 5 on the form write "continued on separate sheet" and at the top of the sheet, you write "Personal history continued"
Education
1. The file does not support the full name of my university, should I just take a printout and add that via writing
Yes, you can do that
Work Experience
1. If I have worked a couple of months in different jobs, but with the same duties, can I join the months to combine them to a year of experience or no?
You should list each of your jobs separately according to employer but you can write a cover letter stating which of your experiences are skilled and should account for your 1 year skilled experience. However, keep in mind that your 1 year skilled experience must be continuous. That is, you can not use it if you had a couple of months, then a gap, another couple of months, gap etc.
Personal Details of your mother
Family name at birth: Should I have my mum's marriage name or her family name at birth here?
If it ask for your mothers family name at birth, you should write her family name at birth.
Dependants
Does that only include children. What I want to sponsor my parents or siblings later on?
Your dependents on your IMM0008 are only your spouse or common law partner and your dependent children. You should list your parents and siblings on the additional family information form. Sponsorship of parents is currently on hold and you can generally not sponsor adult siblings unless you live in Manitoba or Saskatchewan and sponsor them under a provincial nominee program in which case they will also need to qualify with education, funds etc.
Use of a Representative, additional dependants and declaration from nonaccompanying...if I am not using these forms, must I add them in my package to?
No, if they don't apply, you don't need to include them.
In the Document Checklist: There are so many points for the reference letters they asked, must all of them be included?
If something doesn't apply to you at all, you don't include it.