With the departure of Lewandoski, many expect Bayern bring in a proper no. 9. Although Mane isn’t a like-for-like option but I am convinced that he is going to score many goals and almost replace Lewandoski. He might be deployed as a speedy target man, something similar to Jamie Vardy at Leicester City and Kylian Mbappé at PSG. Mane has proven that he can score from all over the pitch, with his decisiveness in front of goal from wherever he operates. So I strongly believe that he can excel as a no. 9, and there is little or no doubt that he'd be great at the job in Lewandoski’s absence.
Bayern Munich are interested in bringing Harry Kane for his place but I don't expect this deal to happen. There isn't any reason for Harry Kane to leave his team now and I don't have an expectation from the team to let him go too. Mbappe isn't leaving the team anytime soon. Jamie Vardy is a good striker really but I don't think that Bayern Munich will think of signing him either. But maybe he could still be one of the last alternatives. They would chase better strikers first.