After further research, it sounds like it could be really simple on this car. Take it to the smog ref and ask for it to be done under the vehicle model year rule. Since it doesn't resemble anything else, it gets designated as 1960 model year, no smog equipment required, CARB legality be damned.
I think it may be a good idea to talk to both a smog ref and a CHP inspector ahead of time to go over what I'm planning and make sure it's going to be good rather than spend all the time and money and find out I have to redo something. I don't want it to be a massive polluter (I like clean air!), but want to have few enough restrictions to be able to make the engine fun. I'm picturing maybe high flow cats would be allowed, reduce some of the junk coming out, and still let me get it up there in power. More research still to come.
I agree, I don't know how all the modded cars running around are passing smog and getting registered since they can't fall under the 1960 MY if they look like a 1999 Eclipse.