Not just gravity plating, anti-gravity stepladders (not quite, but it's the best way to describe the little hover pip that one technician was using in TMP) and cargo dollys/cargo haulers do exist and are seen, though they're mostly confined to the movie and TNG era owing to effects considerations. It's highly plausible that they exist as far back as 'now' and can be scaled up decently.
There's at least two such designs that I know of, though based on the description given for the connector it'd need to have its own life support system.
Yeah, though that has its own problems as far as clearance goes (assuming a perfect fit, a Class F shuttle and a TEU together comes out to about 5.03m in height, not exactly leaving a lot of room for manoeuvring vertically).
This is, in fact, a very large portion of the reason shipping containers took off. It's amazing how much less "breakage" valuable consumables (among other things) suffered once the shipping container was introduced.
Also makes theft a bit more difficult to conceal as something just getting lost in the hold, and in this case another benefit of the closed system would be that it's going to be quire a bit harder to passively collect intelligence on what's being transported.
Though it'd probably work better with @Mechanis pop up starbase concept (since you wouldn't need two Halleys to tend to a single ship, though that's less of a concern when it comes to fleets/their support ships) is there any thought amongst Starfleet for a pod that can be assembled/disassembled on site into temporary 'drydock' (like the sort we see in TMP)? Could be useful for more major forms of damage that can't just be patched up by a visiting Halley popping by and then limping back to starbase.
A problem with that is that the 'popup' would be absolutely tiny, unlike the 20,000,000 ton Pharos class, it would have to fit into maybe a 30,000 ton cargo container footprint. Which isn't all that big, and would have severe space and weight constraints on every component you want to put into it, and would severely limit its ability.
For the record, this is what I'm talking about. Unfortunately Star Trek has given the name to what on earth would basically be the equivalent of a flooded floating drydock.
I do note the cargo pod is big enough to fit one fully assembled warp nacelle. That may well save some few hulls that get stranded due to nacelle damage.
Whelp.
The choice is between being able to triage and being able to fabricate. There is no argument that could be made, short of something the Klingon augment virus turning multi-species and highly deadly, that would make triage a realistic option.
