palpatine knew yoda according to the return of the jedi novelization.
There is an expanded version of the initial conversation between Palpatine and Luke. It includes Palpatine questioning Luke about who instructed him after Obi-Wan’s death; upon discovering that it was Yoda, Palpatine proceeds to mock the late Jedi Master by mimicking his object–subject–verb style of speech. he knew him well enough to do that…which is proof enough for me.