Have you worked out the code, Genius, that is the words formed by the extra letters in the 6-letter clues? If so, you transpose the letters of the actual 8-letter clue answers into the same pattern.
I'm trying not to give the game away, which would spoil things for you and others perhaps. As a matter of interest, the 'I'm' plus 'a crony' answer does not end in 'y' once the letters are altered as above.
15D is not sicanian, though that is on the right lines. Think of the word that is almost always used for 'beers' in crosswords.
I hope I've done the right thing in not just telling you the answers...not deliberately teasing!