Well...
Assuming Eduardo opts out, Baez stays, the free agents move the 40-man down to 37. Activating Alexander, Greene, Meadows, Mize, Pacheco gets you to 42. You have to cut 2. If you want to protect Keider Montero, you need to drop 3.
If you ask me, I'd say Andrew Vasquez, Trey Wingenter, Tyler Nevin, and Brenan Hanifee... But I could be wrong.
You can't outright Kelly or Meadows, so you have to wait to non-tender them. Pacheco also makes sense as a non-tender, and not an outright, due to how minor league contracts work after an outright.
Anybody injured or added to the 40 man after August 15 needs to be outrighted by roster protection deadline or non-tendered if you are going to remove them before spring training. Also, anybody who is eligible for minor league free agency needs to be outrighted before that deadline too, or else you are paying them major league money in the minor leagues next year.