s n and y look good the david is one blob so hard to say then again its one big mess that I really woudnt want to own as there smudges and water damaged
I believe that's Graham Nash by the "S" on the left side of the word STILLS and I have met and gotten his signature several times and it looks like it's real to me.
I think the signatures are likely legit, but I would definitely pass on it. I agree with marc e The poor condition of the piece combined with the smudged autographs is just too disappointing. It might have been a nice piece at one time, but unfortunately it's not any more. Sorry, but I wouldn't want this in my collection either.