20 A Foofoo.
21 D Anagram of 'frosty' and the usual 'hot'. That's a thematic answer - a huge tip to the theme!
22 D. Another odd word. Ouabain, poison. Ou is man (a South African word, I think, but I haven't checked) + A, in clue + B(r)ain ('mind lacking resistance).
Do you have definitely have the theme?