While I think Guyton or Redd has the most potential, I think Stupar is the most likely of the UDFA's to make the roster.
I think it will be tough for a 3rd LB to make the team as a rookie (assuming Mayo and Crable are locks).
OLB: Vrabel, Thomas, Woods, Crable
ILB: Bruschi, Mayo
There is 6 LB spots right there. Seau will make the team if he comes back, Izzo is likely to make the team as a special teamer, and Hobson seems like a good bet to play the strong inside position.
With the number of LB's at 9, then you add in Eric Alexander who has the experience (if not the results) and Bo Ruud who they thought enough of to use a 6th round pick on. I think 9 LB's on the 53 would be the maximum, so neither Ruud or Alexander is in a great spot to make the roster either.
The competition seems awfully stiff for Guyton or Redd to make the roster. Guyton probably has the better chance as he has the build and speed to play either inside or outside. My guess is that for Guyton to make the team he would have to make Izzo expendable on special teams. I do hope that we are able to keep Guyton or Redd on the practice squad if they show well in camp but are unable to crack the 53 man roster. My early guess at LB has Bruschi, Seau, Mayo, Vrabel, Thomas, Woods, Crable, Hobson, and Izzo making the 53 man roster.
At TE on the other hand, the competition is very weak for roster spots. Watson, Thomas, Spach, Pollard, and Stupar are the only TE's currently on the roster. The Patriots will likely keep 3 TE's and only Watson is an absolute lock to make the team. Thomas has been injured, Pollard looked awful the little I saw of him in Seattle last year, and Spach was a late season street free agent signing. I don't have a high opinion of Stupar, but the road to a roster spot at TE seems to be wide open. I do think the Patriots will likely sign a veteran blocking TE at some point, which will make a TE roster spot much more difficult to come by than it is right now. My guess is that Watson, vet blocking TE to be named later, and Thomas make the team. Pollard and Spach are kept on speed dial (like Rivers last year) and Stupar or another teams young TE ends up on the practice squad.