Well you got a lot of info thrown at you there and I hope you aren't more overwhelmed with the Canada/US confusion going on there for a bit.
I just wanted to make a few points in an effort to help out with the confusion:
- The suggestion to decrease the incline on your daughter's seat is a good one, but I just thought you should know that the seat does have to be at a 45 degree angle for newborns, as per the instructions. Once they are a little older and have good head control, some kids are happier a little more upright. I'm not a tech (yet) and I'm not 100% sure at what age you can start putting them more upright. I just wanted to say this in case someone else reads this thread and thinks they don't have to have their infant or convertible seat at 45 degrees for a wee little baby.
- If you spend a bit of time browsing this site you will see that most (all?) people here are big time advocates of keeping your children rear-facing as long as possible (i.e. well past the minimum of 1 year and 22 lbs). There is lots of info here and on other sites about why this is the case. My current favourite links are:
http://www.joelsjourney.org/
http://kyledavidmiller.org/pages/4209/Car_Seat_Safety:_Rear-facing_is_safest.htm
- Since rear-facing is best, ideally you want to purchase a seat with as high a rear-facing limit as possible. The best option for this in Canada right now is the First Years True Fit, with a rear-facing limit of 35 lbs. It also harnesses forward-facing to 65 lbs, and has good height for tall kids. The NEW Alpha Omega/Eddie Bauer 3-in-1 seats also rear-face to 35 lbs (these are just starting to show up in stores now; the older ones have lower limits), but this seat is not highly recommended because of the lower forward-facing harness limit and because it does not make a good booster seat. It is not considered good value for money.
- Other people have addressed the merits of the True Fit and the other seats you are looking at. Just note that the other seats have a rear-facing limit of 30 lbs in Canada.
As for your crotch buckle question, we have a True Fit and it hasn't been an issue for our 19 month old 28 lb boy yet. From what I've read here it seems like the people that might have been having issues (or rather were worried they would have issues when their young kids were older) had kids in cloth diapers and once the diapers are gone there is a whole lot more crotch room available. That is just my overall impression after reading posts about that issue over the last few months; there may still be people who aren't 100% happy with the crotch buckle. I don't expect it to be a problem.
We have a Marathon and a True Fit in 2 vehicles (Ford Focus hatchback and 2-seater Ford Ranger truck) and I'm going to be replacing the Marathon with another True Fit when DS hits 29 lbs so he can stay rear-facing in both vehicles. I like the Marathon, but the higher rear-facing limit and the fact that he looks like he has more room rear-facing in the True Fit makes it the winner.
Last thing, some of us Canadians are hoping that the newer version of the True Fit due out in the States mid-Feb will also come here shortly after. It will be more expensive, but it comes with an anti-rebound bar (like a T that rests against the back seat when rear-facing). The reason I want one of those is because the harness adjuster will be easier to access when the seat is rear-facing which is the most common complaint about the True Fit (but not a deal-breaker). I'll have to try one in my car before knowing if I'll really like it better than the current version, but I'm excited to have the option. Assuming it comes here.
That last bit was my long-winded way of saying that you might want to wait a bit before you buy anything because if you wait you might have another option.
Sorry this was so long.