For the front hubs you might be able to get an undrilled trailer hub that works with the same size bearings as the Cortina stub shaft.
This is probably the best way to go here as it will maintain steering geometry without adding a heap of steering axis offset. That way you can just run standard drive peg adapters like with any other wheel.
The rear is probably a bit easier as you could run a thicker spacer with some secondary drive pegs.