Introducing a SeaTalk-ng MFD to an older 150/400 autopilot

[on the job]

2003.5 Sea Ray 340 Sundancer. Existing is a RL70C chartplotter with radar and ST7001 auto helm control along with a Raymarine Type 150/400 autopilot system. External GPS.

I am introducing a new A97 and a Quantum radar. I have a E66066 Transducer Adapter for the sonar side of the upgrade. I also have a E22158 SeaTalk to SeaTalkng Converter to handle the SeaTalk to SeaTalk-ng.

My current setup has all the SeaTalk running through Autopilot Course Computer. The current GPS antenna is on the SeaTalk A side of the Autopilot Course Computer. The SeaTalk B side from the Autopilot Course Computer goes to the ST7001 and the current RL70C. There is also a NMEA 0183 running from the Autopilot to the RL70C.

My thought was to introduce the E22158 SeaTalk to SeaTalkng Converter to the SeaTalk connection. The SeaTalk from the Autopilot to the RL70C would connect to a D244 block. The E22158 connects theSTng to SeaTalk to the D244. The A97 would connect to the converter through STng connections. And last a 12v connection to the E22158.

My concerns:
1. Would I then disconnect the 12v red lead from the SeaTalk B side or both the A and B side of the Autopilot Course Computer?
2. GPS. Should the Autopilot Course Computer continue to be running from the original GPS or would the internal A97 GPS handle it and I can get rid of the original external GPS antenna?
3. NMEA 0183. It appears to come from the original external GPS. Because the new A97 has an internal GPS do I still need NMEA 0183 inputs? The old NMEA 0183 data appears to be coming from the Autopilot Course Computer which appears to get its data from the external GPS antenna.
4. The connection from the old RL70C that is NMEA OUT I believes connects to the Smartcraft through a bus bar. What is your best recommendation that connection?
Thank you,

John