67 Engine to 72 Trans Question

All three options are viable. My personal opinion would be to swap cranks, if rebuilding the engine, anyway. I have not had any luck finding a machine shop that would/could drill the crank pocket, and the crank would have to be removed, anyway. I have several "hybrid" converters, but they are race units, and expensive. I don't know the price range for a "stock" style hybrid converter.