The short answer is no she never did have a 1 year visa in her name at some point. When she first entered the USA she obtained a 5 year visa using an alias as she was denied previously under here real name. In 2001 when she filed her family petition she was also granted a pardon for using the alias or assumed name. I am guessing all of this may not help our case with immigration canada so we would likely not want to share all of this with them. Would the fact that she has been living in the USA for 15 years (such a long period of time) and has a family based petition ongoing (it is my understanding its just a matter of time until it is approved but could take years but they will not deport her in the meantime) be a reason that she could apply through the buffalo office?
Hmmm... That's not the answer we were hoping for...
The requirement is quite specific - you must have been legally admitted to the US for at least a year in order to qualify for processing through Buffalo. Unfortunately it doesn't look like she qualifies.
As you've said, the 5 year visa obtained using an alias won't count. Neither do the 15 years she has been living in the US (because she has been there without status). The ongoing petition isn't of any help either.
If/when her application is processed through the Philippines, she won't necessarily need to attend an interview and leave the US - but there's always a chance. I see why you have such a complicated situation. I only have a passing knowledge of US immigration policies. However I suspect that if she leaves the country, her family based petition in the US will be terminated and she will receive the 10 year ban for overstay. (And I'm assuming you want to avoid the US ban if she has family there and wants to be able to visit them.)
I feel for you. You're facing a really tough situation. Even if she doesn't require an interview and is approved for PR in Canada, I think the US overstay will still be a problem if her US family petition hasn't come through by then (i.e.when she leaves the US to land in Canada she will be slapped with the 10 year US ban).
Do you have any idea how long it may take for the family petition to be finalized? If it's a year or two, it might be worth it to wait this out and obtain status in the US first (to avoid the ban).