I'll bite on your predictions. I can't fault you for being creative and I liked the read, even if I disagree with it.
One - Assume you mean TMarshall will move to AB? If you are talking Marcus Marshall, no way. We have so many ABs on roster - we are already 3 deep there with Searcy, JJ, Lynch, Cottrell, Willis, Griffin. Not even counting TaQ or Matthew Jordan.
To me, Leggett and MMarsh are locks for BB. One of Q and MLD, imo, will be moved to AB.
Two - I also think chances are slim Lynch moves to WR. He's was by far our best AB at the end of this year. He was just a freshman and he's only 6'0. Lynch is not going to sit on the bench at all - in fact I bet he and JJ Green/Searcy will start. We are also very deep at WR. Jeune, at least to me, looked great at times. And he was only a sophomore. Toss in Stewart, Howell, and Philpott and we've got some talent. Lynch would spend just as much time on the bench next year rotating in and out with those guys as he would at AB.
Really goes back to the old "if it ain't broke, don't fix it" - if Lynch is such a great blocker then let him block for our ABs. Let him catch balls as an AB.
In terms of St Amour - I think he ends up taking the DE opposite KeShun and also fills in for him at rush end at times. Not sure where you got the 250 thing from (don't disagree with it, I just don't see where it came from), but it's a big step to get a guy listed at 240 this year all the way up to 275 - not to mention that 275, frankly, is a bit light to be playing on the interior anyways. And, in your scenario, next year he'd be playing inside at 265. Sure, it's possible he could generate a pass rush from inside. But he could also be blown up on run plays pretty frequently. Between Gamble, Cerge, and Kallon, that's a good inside rotation. It's also possible Freeman leaves early next year, so I don't know why you'd convert your second best pass rushing DE to DT so readily.
Agree on Jordan, assuming Timmy doesn't get an extra year.