[AltSaint]

Something slightly more sensible than my first suggestion goes back to your option 1. It means you must have a freediver confident in doing deepwater rescues, to 33 metres ( and who doesn't get involved in the rope pulling! ). When setting everything up, once you have let out 32 metres of rope, you attach something like a climbing ascender to the rope ( to stop the rope moving past the float shackle in the reverse direction ).

If you have to deploy your 10Kg counterweight, then the counterweight shouldn't be able to make contact with the victim, assuming he is dangling down from the plate.

The safety diver should be able to descend at the same rate as the descending counterweight, and if for any reason the victim is further up the line, then move either the weights or the victim.

It's not completely ideal, but then neither is any counterweight system.