Hi, I just call CIC to ask about the first question, actually, asked for myself but update here for you too.
For example of my case, I came to Canada first time under Visitor visa in 2006. And the last time I came to Canada under work permit from last year.
So, number 7 I will put my first time in 2006 and number 8, I'll put the last time. Number 9 will explain for number 7. I did ask CIC if I don't have any info or papers in hand for the first time anymore (since it was too long), they said it's ok, no worries.
If you wife just came to Canada one time and stays until now, you put the date she arrived at the airport into number 7 and leave number 8 blank.
Hope it helps!
For example of my case, I came to Canada first time under Visitor visa in 2006. And the last time I came to Canada under work permit from last year.
So, number 7 I will put my first time in 2006 and number 8, I'll put the last time. Number 9 will explain for number 7. I did ask CIC if I don't have any info or papers in hand for the first time anymore (since it was too long), they said it's ok, no worries.
If you wife just came to Canada one time and stays until now, you put the date she arrived at the airport into number 7 and leave number 8 blank.
Hope it helps!