Ranch home, CZ 6 with 99% design temps of 89°F and -9°F.

Load calcs done with HeatCAD and I'm fairly well versed in load calcs and construction. I've made the assumption I can achieve <1.0 ACH50 and won't stop sealing until it's well below that level. R22 below grade ICF and R22 or R30 above grade (more on this later.) R6+ windows and the percentage of glass is relatively low. Plenty overhead and under the basement slab as well.

Max heat load: ~35,000 btuh. The walls are the largest factor, but raising to an R30 saves just ~2,000 btuh peak load making it relatively unfeasible. Max cooling: ~19,000 btuh.
The heating and cooling loads are around 6,000 btuh in the lower level and the remaining is upstairs.  This is/was expected.                       

The home is fairly well open concept with the great room, dining, kitchen, foyer, and even laundry are essentially wide open. The bedrooms (three on main) and two bathrooms are obviously separated by doors for privacy and minimizing the open-concept in those areas.

The load calcs are at home, but I'd like the greatest minds to let me know if the following is idiotic or not. (I'll update ASAP with actual load calcs in hopes, if nothing else, someone can let me know if I'm WAY off base or not. EDIT: I tried to upload the pictures, but the limit is 100kb. I'll get the prints uploaded asap.)

I'd really like heating and cooling to be done by split systems. Conceptually, I'd like a centrally located ceiling cassette on the main floor and one in the basement, located in the great rooms on both floors.

I believe I'll have a hard time with the minimal airflow, but is it feasible to use an ERV to draw air out of multiple areas of the building only to be replaced by air in the 'common areas' which has been conditioned? I intend to draw it out of the bedrooms, restrooms, etc. and put the fresh air into the great rooms. Additionally, I would expect to need a whole-home dehumidifier could potentially pull air out of the same areas (minus the restrooms for the sake of smells) and discharge dehumified air in the great room.

(note, I can't stand much noise which is why I'm headed for ICF and trying to eliminate a traditional ducted system. Additionally, I can likely mount the cassettes and condensers by myself vs attempting to run copious amounts of ductwork, etc.

We got our full ICF house down to .78 ACH without much work. The biggest help was using a thermal camera just after drywall was up and not completely finished. Where there was cold spots I drilled a hole and squirted in spray foam. Make sure you get a foam gun and not just cans. This was a 3700 sqft ranch with walkout basement so a lot to cover and the thermal camera made it quick and easy. The cameras are like $200 and attach to your cell phone.

We are in Zone 6 Michigan. We have heated floors and can use a wood burning to do most all the heating if we want and in the summer I just run a single sprinkler up to 6 hours to cool the house(most of the time it is under 2 hours). The sprinkler water for the grass is ran through the heated floors first and that does all the cooling. Our well water is 50 degrees. We are a Build Block house with R30 on the upper floor and R22 for the basement. Both are 6 inch walls.

I ran our EVR to each of the bathrooms and have it sucking air from right next to the toilet seat. This has worked really good. It takes the humidity out and the smells......It sounds like you were thinking along that line but do place the suction right next to the toilet. We have Smarthings automation and when someone enters a bathroom the EVR is turned on for 10 minutes. It is silent and the fresh air is returned into the house in the basement. I feel this way the fresh air is flushed through the whole house.

Good luck, sounds like you are on your way to a great house. We have also added solar and are nearly net zero for heating/cooling and electric....

If you make your bedroom doors leaky, that ventilation will probably work but it might make noise issues if someone is being noisy in the great room while you are trying to sleep.