I made the same migration, but I did it all at once -- ripped out all the
Raymarine stuff and started over from zero.
You can use NMEA0183 data in the Zeus, but the Zeus has only one NMEA0183 input, so the data needs to be multiplexed before it gets there.
It will
work much better with NMEA2000 data.
The B&G Triton displays are wonderful -- if you do a search, you'll find a lot of information about them here.
It would be a shame not to have the pilot interfaced to the plotter -- no nav mode, no routes, and no pilot control from the plotter (very well implemented in the Zeus). If I were doing this and couldn't do it all at once, I would probably make a new Simrad/B&G pilot controller a priority.