The Pats coverage schemes involve so much man-matchup and "pseudo-zone" pattern-matching (that also involves the safeties), that I'm not certain how relevant the traditional LCB v. RCB distinction is anymore. I'm not saying that it's totally irrelevant, just that there's been a lot of game-to-game variability, and that player versatility is key to providing those coverage-disguise opportunities.
In Buffalo, Gilmore started some at LCB and RCB, and even played some slot. AFAIK, J-Mac has made significant numbers of his starts at both LCB and RCB. There could be a lot of matchup flexibility there.
In his time with the Pats, Rowe has been exclusively at RCB, but was tried out in the slot with the Pats in 2016 (mixed results - but Ryan ended up playing mostly slot during the second half of the season with Rowe at RCB).
JJ played most of his 439 D-snaps in 2017 in the slot, but was sometimes matched-up such that he lined up as a perimeter corner (and did well).
Dawson, IDK what roles he may be capable of handling, but I would be very hesitant to pigeonhole him as exclusively a "slot guy".
It's perhaps worth noting that Butler played almost exclusively at LCB. That may have been a drawback.