Mostly right for the answers, apart from -
16 - ??AT - take 'r' out of a 5 letter word for 'beginning'.
21 L????R? - def - 'away from the wind' - 'fish' = EEL (backwards).
29 (down) is thematic and 5 letters long ?[??]R? - take the 'o' out of the obvious audio system.
But wrong on all of the 'extras' -
2d - No extra word (I gave the thematic answer for that one earlier - it's 8 letters).
3d - No extra word (I also gave the answer for that one earlier).
9d - No extra word (I also gave that one earlier).
19 - No extra word (I also gave the thematic answer for that one - it's 8 letters).