I’ve long hoped that some director would use a bunch of established porn stars (clothed) as extras and in bit parts in their movies. The trick is that each of them probably has several thousand fans who would buy the movie just to see the recognizable face, and them doing normal, non-porn things.
Importantly, in most cases they only need to be in the SAG union if they have speaking parts, but if they are just doing things in the background, even if they are eye-catching (still not porn), without speaking, they don’t have to be in the union.
I see the error in your strategery...