Pretty good analysis so far, but some corrections and additions:
McGuinn and McGuire are Roger McGuinn and Barry McGuire of the Byrds and they couldn't get much higher refers to their hit "8 Miles High".
Zal and Sebastian are Zal Yanovsky and John Sebastian who started the Lovin's Spoonful, in their early days singing in clubs and coffee houses.
Mugwumps were the Mamas and Papas before changing their name.
Pretty good analysis so far, but some corrections and additions: McGuinn and McGuire are Roger McGuinn and Barry McGuire of the Byrds and they couldn't get much higher refers to their hit "8 Miles High".
Zal and Sebastian are Zal Yanovsky and John Sebastian who started the Lovin's Spoonful, in their early days singing in clubs and coffee houses.
Mugwumps were the Mamas and Papas before changing their name.