Lawrence, Pereira and Henriquez for sure. Micheal Keane, Varela and Saidy Janko too. Janko will mainly be cup games for a season. Others can be backup 1st team members. Pearson and Charni Ekangamene after a year or two, maybe? If they get the right loan spells.
I personally declined to send any of the above on loan in the short while I used LFC Marshall's update (Nothing against the update, which is excellent, but I prefer the 14.3 DB, so that when I get FM 15, I'll have atleast something to look forward to, in a new unplayed team).
Anyhow, Pereira can already be pretty good for Rotation. Henriquez as an impact sub is excellent. Lawrence, more along the lines of backup. With good tutoring, he'll be brilliant in the 2nd season. If you're using Phil Jones at CB instead of RB (Ingame, I still feel his best role is RB, he's outstanding there), then Varela is definitely rotation option. Janko, Pearson and Ekangamene for cup games, until a season or two.
Finally, it'd be pretty interesting to see if you're bringing United youth through, and how they progress. Haven't seen that in a while.. xD
Unfortunately, Blackett and Reece James still seem kinda crappy, hopefully, with their recent performances, that'll improve..