I may be wrong on this, but I was under the impression that "Unlikely to be attained" just means that the levels of those metrics in question (i.e. Number of TD's, receptions, yards, etc...) are higher than the player's previous season.
For example, Moore has one TD last year. If the incentive was 2 TD's, then it would be considered "Unlikely to be Attained", based on the previous season (even though with Allen tossing the ball, on Brady's offense, one would imagine that they ARE, in fact, likely to be attained).
I believe that's how it works. Only incentive metrics that are at or below the previous season's would count against the cap.