I find this to be a reasonable framework.
However, I would note that we are fine without the 5th DE, 6th LB and 5th S. The last few roster spots could filled by almost any position for reasons of development, the need for more positional depth, or to add to our Special Teams strength. I accept a 5th corner as part of our rosters since the NFL has become a passing league. Clearly, we have had fewer under Belichick.
DEFENSIVE POSITION #23
We seem to be committed to TWO positions for developmental safeties Wilson and Harmon). That makes life a bit difficult. So, one of last 3 defensive positions is the 5th safety.
DEFENSIVE POSITION #24
I strongly favor 9 DL's, so I would include the 5th DE, who also might be a swing DL like Cunningham.
DEFENSIVE POSITIONS #25/#26
I could see us keeping the traditional LB/ST as most of us do. This player could be added after Game One, and more during the year (as seems normal).
For me, this is more a Special Teams position that a LB position. We seem a bit light. So, I would think the competition would be between the LB/STers, Cole and Ebner.
And yes, it reasonable for us to fill two such positions, taking a position from the offense.
DEVELOPMENTAL PLAYERS
Many of us have the following on the 53 man roster: Bequette, Buchanan, Beuharnais, T Wilson, and Harmon. I am finding it a bit uncomfortable to have so many developmental players who may produce very little this year.
New England Patriots Defense (positional distribution):
Defensive End - 5
Defensive Tackle - 4
Linebacker - 6
Cornerback - 5
Safety - 5
Practice Squad (positional distribution):
Defensive End - 1
Defensive Tackle - 1
Linebacker - 1
Cornerback - 1
Note: Practice Squad - 4 offense, 4 defense