I can't really tell how serious Bayern Munich are concerning this deal, for now they are just speculations which seem unlikely to me. Harry Kane has always been a die-hard Tottenham player it will take a mind blowing offer to convince him to switch sides and join Bayern Munich. Bayern Munich are in need of a striker but I think Tottenham also need his services and might not be open to letting him go this January.
I think that if Tottenham isnt in a good position in the premier league and the champions league that he might leave for sure for Bayern Munich. If the transfer dosent happen in the winter transfer window it will happen for sure in the summer window. Kane would be a great addition to the Bayern Munich team and would win a couple of titles finally.