I am trying to imagine where the flat pieces with the square cutouts will go (lower part of your center picture) if they are even part of the same project.
My guess is they went into that pie in the background for a carousel or HDU.
I see the lifting points you mentioned, hadn't noticed them before.
Are ROVs and cable heavier than a logging tool? "I wonder if it might be a proteus type compensator for a heavier winch load but possibly a shorter maximum heave specification. "
A shorter maximum heave specification would probably work for an ROV, they don't usually go out in the roughest seas with the strongest currents. I'm not saying it is, only that it could perhaps be a modified Proteus frame.
"Q: will the LARS have a broader market than the proteus or are these two items on par in that regard?
A: the LARS probably has a broader market because not all applications require active heave. proteus may or may not be a complement to a LARS unit. in other words, you need a LARS to have the proteus, it's not the other way around. there will be some applications that require a LARS with a proteus attached.
My posts are my opinions. Always dd to your own comfort level.