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Glen, nice work. 

A couple of questions, have you done anything to the units? Charged them up? Pulled them out and cleaned the coils? These are some options as well. 
Really it also depends on how you plan to use your coach. If you are going to be doing more boondocking you may look into one of those other options. There are quite a few DC air conditioning options out there. I have a buddy that put the Cruise and comfort dc system on his bus and he is quite happy with it. He said they were very helpful in helping him figure out what would work best for him. I am thinking about this as an option, I really thought it was going to be expensive but really they are comparable to the cost of a roof AC now. 

https://www.cruisencomfortusa.com/

Here is a video of an install of this system, may not be the best install out there but it gives you an idea:
https://youtu.be/NZJGYYkSa_w?si=mNCnAfCgk2ajX3n3

I have not done anything with the existing units, but I don't know about previous owner.  I have not charged them up, or pulled out to clean the coils.  How hard is it to pull out the unit to clean the coils?   Looks heavy.  And I will want to do that.  I am guessing a lift table will ease this process.

I do like that Tito in the video does use a DC system offloading the AC inverter system. I am guessing that using my 48V batteries as the power for any additional unit would be the right way to go.  It is also imperative to minimize additional noise and would look for one of the "quite systems" if they are what they claim.

Most of my use is boondocking, but I do sometimes have hookup when Sara picks our destination.  During travel, we normally do not stop at an actual campsite so nights on the way to destination or unhooked.

The units are not too bad to get out. Depending on how big you are, you can actually just slide the unit and spin it to one side and there is enough room to get in to the plenum area. I slid them on to my hand truck but a hydraulic table or motorcycle jack would both work nicely to get the unit out. As Richard said, they do not have service ports on them so to charge them up its a bit of a project, but you may want to verify the amp draws to see how the units are running. One of my units was not running the second compressor because the control board was damaged. I ended up abandoning the control boards and created my own controls based off a house thermostat and relays. 

Here is my thread about my SCS modifications:
https://newellgurus.com/showthread.php?tid=7503