If all 3 were available, and they wont be, but in this hypotehtical, it's -
Quinn, Peterson, Landry
I like Landry alot. Great tackler for one thing. Good speed. Has all the tools you are looking for, but he is a FS for crying out loud. How many plays will he have a DIRECT impact on as opposed to a RB or QB? If these two guys are gone, I am ceretainly ok with Landry, but I might be tempted to go with Levi Brown, or one of the excellent Dlineman instead.
So, for me, it comes down to Quinn or Peterson. Looking at our current roster, after resiging Dayne and signing Green, we already are good at the RB spot. In addition, RB's have a short shelf life and AD has been injury prone although I am not extremely worried by his injuries. If all three were on the board, and they selected Peterson I would not be upset at all....but...
If I were picking, I would take Quinn. Carr is garbage. Sage is very unlikely to be the long term answer. A QB touches the ball on every offensive down and is the most important player on the field. A good QB can play at a high level for 12-15 years, and they are vital to the long term success of a franchise, and are far more important than any fs. I see some Matt Leinart in Quinn, and feel he will be a fine pro player. How good is open for debate, but I do not see this guy busting. Of course, there are no guarantees, but players bust at every position. Anyone remember Aundray Bruce?