I’ve heard Tawny Newsome talk about this show on a podcast, and in this particular case, it’s the opposite - Paramount+ wanted a live-action comedy, Kurtzman wasn’t sure it would work, and Newsome had to talk him into it.
That said, the industry as a whole has been in a state of contraction, and the big Paramount merger is imminent, so who the hell knows what will happen?
Yeah the Defiant crew size seems to be ~50, per DS9.
However, on a three-shift rotation, only around 16 or 17 should be on duty at any given moment - the rest would be asleep or doing whatever passes for recreation on a ship that size. So yeah, 14-16 on-duty crew at any given moment actually seems about right.