This is evident for their pre-season matches even though there is no Lewandowski but their productivity is really good although it still can't be used as a benchmark in my opinion.
At the moment Naglesmann has really made Mane fill in the position left by Lewa and this is still going well with the goal he scored in the friendly but it looks like he has to work hard now.
I guess there is not much you have to do with a player like Mane is to get him integrated into a team , specialy for Bayern Munich.
I would be not surprised if we will see Mane on the Lewandowski position , Gnabry and Mane looks also a good combination for what i have seen.
Mane is a wing player so he is not an actual striker so i dont if he can fill that role 100%. Maybe Muller will play the striker position now but i still think they need to sign a striker. Both gnabry and mane are wing players aswell as sane. Bayern munich needs a striker and fast
He is not only a wing player , he can play more positions and he already said in some interview " He will play every position where the coach will want me , but not as a goalkeeper "