Conditioned attic space, existing construction blended with new add'n

We are a GC in the northwest, but of a different caliber. Much of our work is design/build. While we depend on designers and architects, we do many of our own details, based on standards described by technical professional groups - Exterior Design Institute and RCI being two. A current project challenge is the Architect has left roof ventilation / conditioned attic space to us to propose. Customer is convinced that a metal roof is in their best interest, and I would have to agree. Architect: "...if you can't vent it properly, condition it...".
Hip roofs, shed roofs, vaulted ceilings, 10 skylights. Very cut up and not that big.
Q: Hip roof on the new construction addition, no ridge to vent and can vents would stand out. Spray foam has been suggested thus conditioning the attic. ? Are there details available for applying foam - where, thickness (Code driven), area to be covered, remove all potential ventilation. Just not sure on it's installation.
Q: Existing shed roof aspect at two locations of the structure- venting is currently employed, but 2"x8" framing might limit the amount of insulation on the south and west exposures. Can we consider conditioning this space and eliminate all venting? Many skylights here.
Thanks so much.....