Re: acid casualties... Peter seems pretty coherent and often very sly in the great Man Of the World doc. I loved the closing bit about being a better musician than Sooty though maybe not with Sweep!
The Munich commune visit makes a great spooky story, but seems like Peter was uncomfortable with fame and fortune before then, and Danny took a few years more to suddenly have been effected and then still played great and created original material post FM. I always wondered if Yes might have been a great fit for Danny? I'd definitely rate him as being as good as Peter Banks (r.i.p.) or Steve Howe, two other favorites of mine.
Anyway, I've met musicians claiming over a hundred acid trips who are totally coherent and sharp (into their '60s anyway).
I really think Syd was going to be how he was regardless, just a question of degree perhaps.