The art's very odd in that some of the real people are really easily identifiable...others...not so much. (Fictional characters are easier, of course.)
It would have been easier if they'd gone with caricatures for everyone (as with de Gaul), instead of mostly just slightly cartoonifying them.
For instance, I'd have never recognized the Monkees, were it not for Peter's hat - Davy looks more like Walter Koenig, and Mike's unrecognizable...Mickey's a good likeness, though.
Chaiman Mao, I'm still not 100% I've ID'd correctly, but I know he's there, so that must be him (wedged in among Dylan, the Monkeys, Muhammad Ali, and LBJ*)...
* I actually have no idea how I recognized him...it was the hat which consciously caused it to click, but I don't actually remember seeing a picture of him - either photo, cartoon, or caricature - which featured a cowboy hat.