I'm not familiar with the term, Choice seat. AA uses the term, Main Cabin Extra (MCE), to denote the seats with extra leg room. On all configurations of the 757, the MCE rows are 22, 25, 27, 30, and 33. This is according to the official cabin equipment diagrams. The designated (for the reason I first gave) exit rows are 9, 10, 17, and 18. So, if seatguru is telling you that the seats in row 10 are Choice seats, they have their own definition of Choice. The pitch is the same as all other coach rows except the window exit rows (17,18) and the MCE rows. I mean they are close to the lav, and if you are at an airport, such as MIA or MCO, that uses the 2L door for deplaning, you get off the airplane pretty quick, but "Choice?"
The main problem with 10A and 10F is that there is no underseat stowage. Just as with any bulkhead seat, everything has to go in the OH bin until after takeoff. There is lots of legroom in those seats since there's no 9A or 9F, but no you can not slump down in the seat and put your feet up on the slide bustle. I know you know that, but most passengers see no reason why they can't do it.
The only other difference in the 3 757 configurations that I know of is the number of seats in FC--16, 22, or 24. I think the 16-seater is the "International" version and FC is called Business Class. IIRC, that configuration uses a more reclinable seat, not "lie-flat", but more than usual. But, I can't swear to that. I've never done an International flight, and at 13 years, I'm not senior enough to hold a 757 line at DFW.