Now that they have turned around the game against Copenhagen and got their full three points, it is highly unlikely that they could still fail to pass the group stage in the Champions League. They haven't lost a single game in the group stage in years. The game against Galatasaray in Istanbul will not be easy and the game against Manchester United in Old Trafford will also be tough, but they don't feel the pressure anymore that they have to win every game from now on. They will be doing fine if they win their home games against Galatasaray and Copenhagen. That will do the job for them. But the goal will be to win the group of course as it raises their chances to avoid to play against a heavy weight in the round of 16.
I am with the prediction that Bayern Munich will top the group. When the group seeding was done many actually had a prediction of the top spot been between them and Manchester United but with the way United are playing they would only get second best in the group if they even qualify. The big threat to united will certainly be Galatasaray, they have been one of the hottest clubs in Europe this season and if Bayern can beat them in the two legs and United produce same result in the other game with Copenhagen then Bayern will have save them selves the top spot. And this is something I am speculating to happen except we see a very different Galatasaray.
You summarized it quite well and I think the threat from Galatasaray is bigger than some might think at the moment. The problem is not that Manchester United lost one game against Galatasaray, the problem is that they lost their home game against Galatasaray and for everybody who thinks that nothing is lost yet and Manchester United just has to show some quality and beat them in the game in Istanbul, those games are like hell with the Galatasaray fans backing their team. For Manchester United I think the game against Galatasaray will be no easier than the game against Bayern when they played in Munich. The atmosphere and then also the quality that Galatasaray has at the moment both makes me believe that Manchester United will not win that game. And if they don't win it I think they can't qualify for the next round in the Champions League.