Depth for a Product Upgrae

I'm going to upgrade an older Raytheon/Raymarine system and need help with the Depth part. I want to update to two 12 inch eS systems with a Quantum Radar. That all seems easy enough. What do I do for depth? The current system has HSB Series Chartplotters and an L760 fishfinder. It has an Airmar Bronze Triducer Multisensor transducer. I guess I could just take depth from the network, but what's the best way to upgrade. This is a trawler yacht, so not doing any fishing, just need accurate depth for staying off the bottom.

Also, with two eS chartplotters, will they share the Navionics chart card?


Thanks, Hube