Now, I could DEFINITELY be wrong on some of these. But...
I don't think there is a Harpsichord. Maybe I just missed it if it's low in the mix.
I'm absolutely certain the piano is Grace. I think all Piano on airplane records is Grace. Except for on Volunteers, that's Nicky Hopkins (although she does return to the instrument for Eskimo Blue Day). I think the piano is the instrument she used to compose her songs, except for Lather, probably.
The wind instruments, I'm a little hazy. BUT I don't see anyone else credited for them in the liners, and Grace does play TONS of recorder on Pillow and Baxter's. Anyone else notice she just kinda dropped the thing around Crown of Creation? Such a shame... I thought it sounded really neat. So I wouldn't be surprised if she plays all those horns and such. She does mention patterning them after Gil Evans, somewhere.
"War's good business, so give your sons
But I'd rather have my country die for me" ~ Grace Slick, Rejoyce 1967