50 points is a really tough amount for a rebel player because it pretty much disqualifies you from using your unique pilots. If your opponent has enough ships to fill out a decent 60-65 point squad, you can really have a lot more flexibility with upgrades/uniques.
As for your 50 point squad, R2-F2 is a waste on Red Squadron Pilot. R2-F2 really only pays off if you have someone who can buff it with an additional action (e.g. you play R2-F2 on Biggs and then have Garven give him a used Focus token). Also, you shouldn't accumulate too many stress tokens with your Y-Wing because you've got the benefit of 360 degree firing arc. For 50 points, I might design the following squad:
Total Squad Points: 50
Pilot: "Dutch" Vander
Pilot: Rookie Pilot 1
The downside with this list is that your X-Wing will be firing late in the round. The Ion Cannon will have to attack first, so you may have trouble hitting if your opponent likes to play evades. Use target locks on Dutch every single turn and use the re-roll to maximize the chance of a hit. Don't be afraid to run red maneuvers with your Rookie because you'll have an R2 unit to pick up the slack. Don't ever use a red maneuver on Dutch - just keep him flying near the Rookie because his facing doesn't matter.