Undercover deployments and shipping of weapon systems could be a thing. But these radar systems and ramps need to be hidden container until they are used, its still pretty hard to hide with cameras everywhere.
Treat this as a proof of concept phase.
If they really wanted to it wouldn't be that hard to have specialised 2x1 or 2x2 containers that can open and jack up things like off-the-shelf radar panels that don't want to hide nicely into a single 40 foot container. The flipside though is the loading becomes conspicuous and not so easily done in plain sight. (Not an issue if there is no intention to do a covert role Q ship thing)
They probably have some ways of battery swapping, by having supplies ships replenishing with a new batch of batteries. There is no need to recharge those lithium batteries.
I don't know of any container ship capable of doing UNREP with full TEU containers. Likewise, doing it by the pallet loads is just tedious and requires crew training ... something which does not fit into the militarising civilian resources aspect of it.
The ship itself should be more than capable of charging a bank of batteries.
Even if the ship gensets are not up to speed, do note that for most purposes, only the top layer of containers are actual payload containers. You still have multiple layers of containers extending down into the hull, almost down to the keel that can be used for gen-sets or all the batteries you could want.
It's really a non-issue
No one has talked about where these systems got electricity. We also one of the biggest challenges for developing modern warships is power management. Civilian ships certainly won't have any redundant power to feed these weapon system and electronic warfares. Let alone an EM catapult. I can't see any container which looks like generator module.
Land based AD radars have no issues working off gensets that fit onto a truck-bed. A container based gen-set won't be hard, there are already COTS generator containers for worksites and HADR use. Just because we don't see them doesn't meant hey aren't there or in the works.
For force multipliers it could be interesting. Support ships could bring some VLS with them, Cargo or fishing ship could start guiding missiles launched from afar with installed radar.
The last thing no one seems to have raised is that when you hang a ship like this out there - in a picket role or a "covert" strike role, it's almost a suicide mission. These ships do not have the physical characteristics to sail out of danger nor the fully integrated and sophisticated defense suite of a fleet to keep them safe.
I have no doubt there will always be patriotic volunteers willing to put themselves in harms way but still ...
99% of applications will be in protected bastions or civil HADR roles.
