Could any Peter Cushing footage in another movie suffice to add Tarkin to the Prequels even for a cameo as an Admiral, perhaps on Anakin’s battalion? Could one incorporate an idea of him being the one to design Vader’s suit?
I could survey his Frankenstein movies but I’m not really sure if one could use material from it considering he spends the entire time in Victorian era fashion.
I had been trying to add Tarkin to the prequels but I couldn’t find the right place (The best I could find was during the scene in Episode II were Anakin transmits Obi-Wan’s message back to Coruscant, with a younger Tarkin appearing next to Bail Organa and Yoda).