There's also Cesar Ramirez, who was a doubles partner of Pospisil in juniors (they made the AO finals). He was ranked #3 in juniors at one point but on the pro tour is nothing special - CH 431. Still he would be ranked higher than others playing, but I guess he is injured as he hasn't played since a retirement in Jan.
The qualifying draw for F1 just came out and I don't see anyone really making it. Peliwo will get Harrison in the second round and ya that about sums up the draws. Di Feo probably has the best chance of making it.