Regina rather than giving your personal opinion please point me to the right link of Canadian cic website so that it will be helpful
And yourself?

http://www.cic.gc.ca/english/study/minors-documents.asp
What part do not you understand :
If a child of school age wants to come to Canada to go to school in Canada- he must apply for SP. No difference with university student.
If a child before a school age lives on TVR with his parent - student/worker in Canada, when it's time for him to go to school- he does not need to apply for SP.
If you applied to your SP AND AT THE SAME time applied for TVR for your kids , and they got it, and come WITH YOU to Canada, then they do not need SP to go to school in Canada.
You could try to get visitors visas for your whole family in a hope that if they get it (I doubt very much) then when they are in Canada they can go to school without SP.
You see? If they ask for visitor visas during school year - they will never get them. During school year kids should be at school on their home country.
Also, what ties do your family have in home country to guarantee to CIC that they will go back when visitor visa expires
if their father already in Canada?
CIC does not allow people to come on visitors visas with intention to study/get married / to work in Canada. There are different visas for that.