How to correctly cite adapted and translated course lecture notes?
For course lecture material, unlike scientific publications, there is no requirement for uniqueness.  It seems that you are giving clear attribution and credit (which can be nicely enhanced by a link, as @JeffE suggests), so I think the only further thing to do would be to drop a courtesy note to the original professor(s) to let them know how you are appreciatively using their material.  Likely they will be happy and knowing that you are using it may even be beneficial to them; in the unlikely event that they are displeased, then you should not use their material (and should ask them to post a clear statement to warn others not to do so either).