Bayern Munich should keep their attacking line as strong as possible as they have started to show a high level performance in the recent times. Mane needs to be treated as good as possible not to miss their PSG game at least. Besides Choupo-Moting might also leave the team as it seems. They need to keep their score contribution as big as possible.
I didn't think moting wanna try to leave from bayern. His performance is so good during the world cup. Im sure that bayern will give him a new contract yet bayern will still need buy a new striker from another club as a replacement for lewandowski. There were lots of rumour about MU will try to buy moting from bayern as a replacement for ronaldo. I didn't know whether this rumour was true or not as there's no talk between MU with bayern about him. For doing this we might see an offensive move in January by Bayern Munich maybe. I actually think that they were planning this for next summer but they might need this even in the middle of the season. The Bundesliga isn't much difficult for them maybe but they need to stay strong for the Champions League.
Bayern has very big chance to win the title. there's no need to worry about participation from bayern in the next season of UCL. Bayern will always be going to the UCL caused by it will always be dominating the budesliga anytime. It wouldn't be logical for Bayern Munich to send Choupo-Moting from the team in January already. Because this would just make things worse in their attacking line. He is already showing an impressive performance as well. As long as they don't think of filling his place with another striker they shouldn't take a big risk considering the Champions League too.
As for a top striker transfer I expect it to happen next summer. Even if they reach an agreement with a player I think it would be just a pre-agreement to finish the deal in the summer. Because they don't seem to be in a hurry to bring anyone in January now. They must be trusting their current strength while they have started to score a lot of goals just as in the previous season.