On a new house that is solar ready (there is a conduit path from MSP into the attic without conductors in the conduit) is a solar company doing the install after the house is final and occupied required to use the interior (solar ready) path ?
IMO no. The "solar ready" path is intended to make the future installation more convenient, but if the solar installer has an easier path that is still code compliant, there is no reason for them to be required to use existing conduit.