A few other kits, if they happen to be lying around your shop, have figures that would be about right. The best may be the old Lindberg WWII minesweeper. It came out at about the same time as the destroyer, and had several figures - complete with Navy uniforms, helmets, and lifejackets. My recollection (from quite a few years ago) is that the minesweeper and the destroyer are on just about the same scale. I haven't seen the minesweeper kit recently; it may be out of production.
I also recall that the minesweeper had a motorization system that was physically incapable of working. It had twin screws powered by a single Mabuchi motor, via plastic pulleys and a rubber band "belt." The water created more drag than the belt could overcome; the belt spun around impressively but the pulleys just sat there. If you tried to replace the belt with a smaller rubber band, it squeezed the pulleys together so tightly that the shafts couldn't turn. Actually the whole problem was rendered moot by the huge slots in the hull through which the shafts traveled. The model couldn't possibly move more than the length of a bathtub (presumably its intended environment) before the hull flooded. But the people were nice.
The old, old Revell harbor tug Long Beach (a really nice kit) was on about the same scale, and came with three nicely-sculpted, vaguely-naval-looking figures. That kit was recently reissued by Revell Germany, and seems to be widely available. Two other Revell kits on about that scale with nautical figures (though they'd need mondernization) were the Santa Maria (seven people) and H.M.S. Bounty (five). The Airfix H.M.S. Endeavor also had some (including one with a peg leg).
Those Revell figures are particularly nice. I believe (on the basis of the recent book on the history of Revell) the masters were all sculpted by the same guy, who also did the figures that came with the Revell military vehicles. According to the book, he was a free-lancer who sculpted miniature people for all sorts of companies. On one occasion, purely on speculation, he made a clay master for a female doll, using his wife as a model. He sold it to the Mattel Toy Company, and it became....
This is turning into an utterly pointless exercise in nostalgia. Sorry. Quite a few good figures for your purposes are available, though you may want to do some subtle conversion to give them a USN look. Good luck.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.