Seacon, Burton and a lot of others make hybrid connector / receptacle bodies but I don’t think people are really in the market to pay the cost of the connectors that you are talking about which would cost more than their ROV for a single set of connectors and the associated receptacle for it.
You say that you are using a cable tether that has fiber optic, a twisted pair and power. Where are you getting that cable from? Is it a total cable or are you making some sort of home made cable?
If it is a true undersea hybrid copper / fiber cable … again, that stuff is going to cost out the ying yang for a system that you are only going to 150 meters with. The hydrostatic drag on that cable is going to be a heckuva lot more than the simple tether system that the OpenRov system is using.
Care to post the specifications for your device?