Yeah in hindsight I agree, Meredith and Harry both have more upside
Meredith is intriguing. Last healthy season was 2016 (so...it's been a while). 66 rec, 888 yds, 13.5 ypc, 68.0% catch rate playing for an awful Bears' offense. He just turned 27 so plenty of tread left on the tires, one would think. Excellent size (6'3", 207 lbs). Career catch rate of 69.9%, which is very good. Comparing that to the Pats' current WR corps...
Meredith: 69.9%
Edelman: 66.6%
Dorsett: 60.8%
Gordon: 52.9%
Harry, of course, is a tantalizing prospect. Also with excellent size and great hands.
Given that they're both already on the roster, and are both making next to nothing, I think it's preferable to see if either of these guys can be an answer rather than go out and spend what's left of their cap space (plus assets to make the trade) on another WR from another organization. The OL needs more help, IMO, and that's where they should spend their trade/cap capital.