15. This is a B clue, with an extra word/phrase - in this case it's Publican.
Coincidentally, you've mentioned 35 A - if your grid's amenable, you could maybe see how these two are connected?
15. The 'contemptible person' is a bit slangy - a three-letter word, also a bird. The fish (inside) is very commonly used in crosswords. The definition is 'American people' - but American people I'd never heard of!