Which date the two year starts to count within the 5 year

[soulfullness]

Dear All
I have a couple of questions.

I have already got the immigration visa for the family and we are suppose to be in Canada for the first time not later than 5th of May 2009.

1) My first question is whether the main applcant can enter the country wihout the spouse and dependent children first as the school schedules of children and my work not facilitating to visit all together. If it is allowed to visit alone , how much fund should I have to take to visit alone?

2) It is said that to maintain the PR in Canada , you have to be at least full two years within the 5 years period. Can you please explain when this date starts? Is it the date the main applicant first enters Canada or the date stamped visa on the passport? The visa stamped date is 6th of August 2008.

3) Can spouse or dependent children can enter without the main applicant for the first time or the spouse and dependent should enter for the first time along with the main applicant?

4) When we return in the future in subsquent trip to Canada, is it required to show again the fund requirement?

The circumstances currently make us to visit at different dates and the above questions are to be addressed prior to make the first visit.

Your commnets and reply on these are highly appreciated.

Thank you all