Insulating attic with no soffit vents.
Is there any insulation now? If not, you might as well go whole hog and make the attic itself a part of the conditioned space. That way, you won't need soffit venting to begin with, along with its associated complications (soffit baffles, ridge venting), and it will also be more efficient if you have mechanical appliances or ductwork in the attic. Get some guys in there to spray a couple inches of closed-cell foam on the underside of your roof decking and be done with the issue entirely!