Of course, it looks like the attacker are finding the right momentum currently. They both scored in their last EPL match which is a sign of improvement in them. I am always worried about United attacking force due to the incapacity of scoring goals, but it seems things are changing gradually. If the attackers can do their work effectively and keep the goals coming, stopping Lyon from scoring wouldn't be a problem.
Lyon are also not very good in Ligue 1 so it will not be that difficult to beat, what Manchester United need to do is find a weak point and they need to score early goals to put pressure on Lyon. But the problem is as you said because Manchester United's front line is not showing its best quality at all so it is much more difficult for them to score early goals.
Not to mention talking about the defense which may not be fully able to play the core players and still looks so struggling to perform consistently so the space for Lyon to score early goals is also quite open.
While the leagues are of course vastly different, Lyon is doing a bit better if I am not wrong. They have 45 points in 26 games, which is about 1.73 points per game, and fifth place at Ligue 1 as well. Whereas United has 37 points in 29 games, which is about 1.27 points per game, and they are 13th in the league. I am not comparing ligue 1 with premier league, of course premier league is harder to do better but that doesn't mean these two teams are close to each other normally.
Just because United is United, people see a chance for them to win, after all they got here so far, so they have a chance to move further too. But I would say if we were to compare seasons, Lyon has been better this season overall than United.