The datasheet (it's a great thing to find such details) of the connector tells us:
Current = 13A max. per circuit when header is mated
to a receptacle loaded with 45750 Mini-FitĀ® Plus HCS
Crimp Terminal Crimped to 16 AWG wire., See Molex
product specification PS-45750-001 for additional
current de-rating information.
The advice of Molex in their additional product specification actually shows, that on a fully populated 24 pin Wire-To-Board connector, the rated current is decreased to 8A per pin:
I wouldn't go anywhere near the maximum on a single pin though, at that current they will get hot (specified to a temperature rise of 30K above ambient at rated current).
So if you spread out the load over several of the 24 pins, you should be fine.
A low quality connector might not hold up to those specs - another reason why not to go to the limits.
Best Answer
Yes, make a custom cable with a 4-pin Hirose at one end and a BNC at the other end.
Similar to this:
This document specifies the Hirose pinout:
This should tell you how to wire it.