I went through LD 5x09 "Fissure Quest" to try and count/estimate the amount of Kims on the Anaximander.
The most we see on screen together not including Lieutenant Kim is 8 Kims on the Beagle Bridge (6 First Contact Uniforms, 1 Voyager uniform, 1 Delta Flyer uniform):
In the scene immediately after the opening credit, we see two non-Lieutenant Kims with the Voyager uniform:
Combining the 8 Kims seen on the Beagle with the extra Voy Kim on the Anaximander, I estimate there to be at least 9 Kims (besides Lt).
However, there are some inconsistencies.
We only see 6 (non-Lieutenant) Kims in the prison, despite it being somewhat implied the Anaximander is mostly empty besides Garak and Bashir:
In one count the mess hall scene, I counted what was at least 6 and at most 11 Kims.
Overall, I'm sticking with my initial estimate of 9 for now.
I wonder what could account for variations in Kims. Were some actually locked up somewhere on the ship? Did Lieutenant Kim forget one?
Also, assuming there are 9-11 Kims, is 14-16 crew (adding Boimler, T'Pol, Curzon, Garak, and the LMH) enough to run a Defiant-class, which usually has compliment more in the 40s? It could be possible that since it's a Section 31 ship that it's outfitted to run with less agents.
P.S I find it a nice bit of canonical accuracy that most Kims are wearing First Contact uniforms (and likely made it home), as since most timelines are close to Prime, uniform designs shouldn't be that different.
I count eight Kims (two of them only partially visible) in that shot of the prison cell, and there's a fair bit of room around the corner for more to be hidden. I think it's also easy to believe there are more cells containing more Kims just down the hall.
It's reasonable to assume that the Defiant class's 50 crew compliment is pretty close to a bare minimum already. 16-17 active at any one time is a pretty short list as it is, with roughly half that posted to the bridge during normal operations and most of the rest in engineering, plus a transporter chief, doctor, and other specialists. Having two shifts of reserves is crucial for covering both a long term assignment and for battle situations: you need to keep the crew as fresh as possible in the long run, and in combat you need those people to fill in for casualties and act as damage control, security, and emergency medical personnel. So unless Section 31's strategic level idiocy extends all the way down to inane meddling in shipboard operations (possible, these guys are morons with dangerously inflated egos!), it should be safe to assume that the Anaximander was supposed to be staffed with about 50 crew.
Boimler also apparently has the mandate to draft every Starfleet member that comes in from another universe, maybe his superiors were expecting him to grow his numbers that way.
I mean his entire command staff is not native to the universe they are supposedly stationed in/ the ship is from.
As an aside do we know what happened to Engineering! Mariner? The ship I think is missing engineering crew and she and William seemed to have a connection.