I didn't get to the symptoms, figured it out as I was wiring. Basically all the simrad stuff has a yellow wire that when given 12V it turns on the device (so long as the main power and ground is connected). The devices can then be set to master or slave, so you can have one chart plotter turn everything else on. I was wiring all the yellows together and then realized after some connection that I wanted the two plotters separate since one was acting as engine management. So now I plan on giving the smaller one's yellow wire a signal from the ignitions (using two diodes) to start up with ignition power. Then the larger one will turn on the network switch, radar, AP. My main worry was I didn't want everything always on drawing the battery at the same time.
I think I have it correct now. Also had to figure out what circuit to power the nmea2000 network off of, how to power/switch on/off the ais etc. Then the depth switch is obsolete since the simrad unit doesn't need the external module. I repurposed the depth switch and breaker for AIS. Just lots to think about.