Full Disclosure: I have only seen the seven movies.
Who all (if anyone) knew that Yoda was on Dagobah? I'm assuming Obi-Wan only knew, because he was a ghost.
[Edit: This will be followed up with a question about Dagobah and its mention/role in stories outside of the movies; therefore the answer should be about characters considered relevant, knowing Yoda was on Degobah.]
[Edit: Anyone relevant; friend/foe or just knew of him before he went in hiding/exile.]