21 Add a letter to the 1st word for the 2 regular letters [inside 1 letter abbrev + 2 letter hesitation].
22 'group' is too loose a def, I think - add letter to 1st word for a 1 letter abbrev + 2 letter abbrev 'lines' also a bit loose + end of ...
24 This is the one I was joking about when I wrote ''Personally I couldn't get into it'' - 'stiff' is slang - and my name is removed... (actually, I enjoyed the puzzle very much}.
25 alternate letters + initial letter of... (and another eviction).