General Discussion

The Soviet Army had women successfully serving in Combat Arms, because they didn't outrun their fucking logistics line.
The operative word is "Army" - not a few dozen Mercenary cohorts that are sent out for a particular mission.
As for fitness?
Heck Look at WWII Colonels and Generals. Most were either very slim or pretty chunky dudes, and certainly not within 10 years of participating in a PT or an obsticle run.
People are going to be as fit as the job they are doing requires. The average grunt that might be humping 200 lbs 2 - 4 hours a day in combat when they aren't riding in a bradly or MRAP is 18 to 23 years old.
85% of the uniformed military are in transport (pilots, drivers), mechanics, logistics, training, IT, analyst, technicians, admin/troop support, gunnery/missiles/drones, medical, construction, engineering ...
Critical positions that require brains and initiative more than Olympic level physical abilities.

If all he wants is a bunch of pretty looking Hollywood Commandos, he's going to be sorely mistaken in what is available.

Or rather,I have a sneaking suspicion all he is there to be is to finish Rumsfeld and Prince's plan to privatize the Department of Defense and turn it into the Department of Expensive Boom Boom Toys to make money and impress the "rest of the neighborhood kids".