There are only 2 squad members that you can recover. I got both pretty much one after the other. They are both available at any point of the game, but I got them both during the mission where you locate the president.
The first is located in Ingleton standing on a bus adjacent from the car dealership. VERY difficult to miss.
The second is in Central City, right by the farthest south safe house location.
Also, if you vote negative please explain why so that I may improve on this solution.