Now that will do wonders for the team's confidence...
There is nothing wrong with losing to Barca at Camp Nou and ManU at OT when you are missing your important players, and if the games are close I don't think it will destroy the players' confidence. If they are out of these competitions, they can only focus on the league, and their run in isn't that difficult. What if they beat ManU? And if ManU drops points in one of the Chelsea games or against Liverpool? None of Arsenal's other games are that difficult, they could conceivably take the rest if they don't have to rotate their squad so much for the other competitions.
The league is the trophy they have the best chance of winning. The Champions League and FA Cup will be huge distractions from that. The former is really, really difficult to win, even if they beat Barca, and the latter just isn't as important, not to mention I don't see them getting past ManU at OT without these players.
I personally just want Arsenal to focus on the league and do whatever it takes so they don't lose any of their remaining league games. If they do that, they have a chance of overtaking ManU even if the game ends in a draw. And if they beat ManU, the chances would be decent. But they don't have too much depth to begin with, and all of the injuries is really stretching it to the limit. I am afraid their squad rotation will cost them the league, and that they won't end up winning the FA Cup or Champions League (and I actually think they will beat Barca, they will just lose at some other point in the competition, and possibly in the final or something, after they had sacrificed the league to try and win the Champions League). This is the problem with Arsenal sometimes. They're a great team that goes far in all of the competitions, but their lack of depth combined with injuries always means they fall short in each one. Their lack of trophies over the past few years is really misleading because of how consistently good they have been. It's just that they don't put all of their eggs in one basket, which I normally don't agree with but this year is a special case. Winning one, especially the league, would be huge for the club and for the Premiership.
Unfortunately, I don't think Arsenal will win any trophies this season, but I would love to see them take the league. And for Barca to win the CL.