Skipping all the RFing debate (and FTR, I am pro extended rear facing but I think other people have covered it). I think people are skipping over a VERY important part of your post. Regardless of height or weight, your daughter can NOT be turned forward facing until she is at least 12 months old. That is a minimum so since she's only got one pound left on her seat but 3 months until she could even legally forward face so the decision on what seat to buy is likely already made for you.
She is in Canada, and I am not sure what the laws are there. It could be 1 AND 20, but I have no idea since I am not a tech there. The seats may or may not specify 1 AND 20 (or 1 year, 22lbs and 34" as most Safety 1st, Eddie Bauer and Cosco seats do).
To the OP, I have no idea why you are sitting in the back. There really is no reason too, so I wouldn't use that to justify turning her at all.
I read a blog, which I would post, but I don't want a lot of traffic going there. Its about an 18 month old boy, who was forward facing, and in a head on collision with his parents. He died. On impact, his neck snapped. He had no outward injuries. Spinal decapitation in infants/toddlers is a real thing, and accidents are the #1 killer of children.
Please, please do your research.