ERV Ductwork in Garage Apartment – GreenBuildingAdvisor

Haven’t been able to find a similar question in the archives so here goes:

Building a 3 car detached garage with a 900SF apartment above built to PGH standards.  Planning to heat/cool with a heat pump in zone 6.  Vented attic above and 15 inch open web floor joists above the garage.  Stumped on locating the ERV and associated ductwork.  There is 100SF of conditioned space on the garage level for entry/stairs.  Option 1 – place the ERV there and run ducts thru floor joists and up walls.  Option 2 –  create a small conditioned attic inside the vented attic to house the ERV and run the well sealed ductwork in the attic under the blown in insulation.  Option 3?

Also, best way to insulate between the garage and the apartment?  15 inches of dense pack seems excessive but not sure what else will work with open web joists.

Thanks for the assistance