Going on his Letterman perfomance, I would say he could do ALL the Uncle Albert / Admiral Halsey high parts if he wanted to. The guy is amazing. The highest note on the 'live a little / be a gypsy / get around' section is a falsetto E. He hit a falsetto E dead on the money in Coming Up on the Letterman show performance. It's the kind of note he won't need to 'reach' for if he just vamps it like he does on the 1971 recording.
And the 'Hands Across the Water' part is a high B, compared to the 'Rabbits on the Run' part in Band on the Run which is higher still, it's a high C on 'rabbits'.. which again, he nailed it on Letterman. I reckon he can still handle these notes. And he has more-than-capable harmony singers with him to back him up. He should do it!