It shouldn't come apart and while I am not about to try I would assume it would be pretty hard to pull apart as I have seen people pick up the radiator and lift the block off the table without supporting it. If it came apart easy a lot of people would have an issue with assembly in a case.

PietroBR
They are supposed to be strong connections.
Some videos that people do some mods on the hoses of these CLC's, they usually need to cut the rubber on the connector to remove it.

I watched that guy drain that AIO and I would be willing to bet that what came out of it was just straight virgin mineral oil. It looks exactly like it in color, viscosity, pooling, etc.... It would make sense in a AIO cause if it leaked you don't have to worry about conductivity, it will lube the pump parts,well...the ones it could reach anyway, evap wouldn't be much of a issue and galvanic corrosion wont happen either most likely, as long as the trapped air doesn't condensate. I guess it could be a glycol but its not necessary and def more expensive that way to make a special formula for AIO's.