Yep, a 43 Alpha-Q will result in 55 trail on the 56 CR whereas 40 will get you a smidgen over 58. My thinking was the Edge/Enve's shorter axle-crown distance would rotate the front end down and back slightly thus increasing trail (numerically) by a mm or two, but considering the entire front end is moving together I think any resulting change in trail will be moot. Also, taking into consideration that I usually run 25 tubulars (27 Pave Greenies currently on the Compact) is probably larger than what most riders would use on a CR will probably further offset any potential change in trail.
Please correct me if my thinking is flawed, it's a little bit of a learning curve for me. I usually just go with whatever fork came with the bike or what the manufacturer recommends. I'm beginning to learn that choosing the proper fork can have a profound effect on the bike's handling.