Update and Question:
Update; HVAC started Thursday on total new system, went with a fully self contained for better or worse. All new Pex installed along with entirely new drain system, I didn't like the way sinks and showers dained into a small pipe that ran a good ways up the home before dropping into the main line and coming all the way back down the home.
Question; As I said before I have removed all the walls and changed up the floor plan a little. I now have the shower and toilet in it's own room with the vanity outside in the main master area. The original large round hole and roof vent for the exhaust fan will now be over the vanity and not in the room with the shower so I will need to install a fan in the shower area and pipe over to the vent. Has anyone had any experience with this and is so is there an easy convert from the large round vent down to a flex duct like the new fan will have? Also I guess I'll be needing advice on patching that hole in the ceiling after the install.
Thanks and I sure hope to be able to offer advice rather than ask for it so much as soon as the project is complete.