I went for someone new.
Rose is poor and should be sold, I don't buy the whole "he's young and will improve" malarkey and we could probably find someone willing to pay a decent bit of money for him (Sunderland if they stay up). I also don't like Rose's attitude, when he weren't first choice there were constant bitching statements coming from him in the press, he never acknowledges the fans, even when the manager has told him too (someone picked up on that on Twitter, mentioned Tim told him to salute fans and he just ignored instructions and walked down tunnel).
Benny is aging and I doubt will ever get back to his best, a season in the Championship won't have helped him, he's been up against lower quality for a year and so if he were to step back into the Prem as first choice, he'd probably need time to adapt to the pace again and at his age, it's a long winded process, so I'd either sell him or keep him as the back up.
Fryers looks a decent prospect but needs a run of games, a loan to a Prem side or a top Championship side next season would be ideal for him.
As for a new LB, there's a few decent options in my opinion. Criscito was one of the names I've mentioned in the past but his fee may have just slightly risen a bit seeing as his manager is AVB now!

Ben Davies of Swansea looks a good talent, 3 years younger than Rose and already better I'd say.
Juan Bernat of Valencia looks similar to the player he's replaced - Jordi Alba - in my opinion.
Jetro Willems looks like a great full back in the making and if the van Gaal story is true, then there'd be no better manager for him.