Bayern already has 5 CBs, though for what I know Sakho can also play as an LB. Interesting player no doubt, very talented, but is he what Bayern needs at the moment?
Atleast Im glad Bayern have options, personally I would reconsider both Demichelis and Van Buyten. Some fresh blood would do good in center defence.
Coentrao would be a fantastic addition, imagine Lahm-Robben and Coentrao-Ribery, quite a force indeed.
On Gomez I think he will go nowhere, Bayern will give him more chance, he did cost 30 million after all.