Best way to connect Simrad MSD50 drive to new es78 MFD

[RockSteady]

I have a OMC Cobra, cable driven, power assisted sterndrive on 24 ft Trophy. My primary need is to steer the boat while trolling. I recently bought a Raymarine es78 MFD. I would like to steer the boat from the es78 while keeping my existing Simrad MSD50 electro-mechanical drive and Simrad RS300 rudder feedback unit as both are in excellent condition. Down the road I would like to add a P70 or P70R at the back of the boat or maybe a hand held remote. What alternatives can you offer to go about this? I don't quite yet understand whether the Evolution 100 series is capable of doing this? If not, is another model like the 200 a possibility? Or just stay with some of the old Simrad junction box, compass, etc.? The MSD50 is 12 volts and draws 3 amps. The manual states it generates a feedback signal. If you could provide a overall summary what you might recommend with list of items needed, that would be great.