If a non-technical founder wanted to "interview" me, I'd tell them to shove it. If they wanted to have a conversation about how we could bring our complementary skills together to solve a problem, then I'd certainly be much more interested.
Also, the popular perception between technical co-founder and early employee-CTO is very blurry (unless you go by virtual vs. real shares). Some people will call a CTO that joined 3 months into the project and holds 10% virtual shares a co-founder and some people won't. Same goes for "technical co-founder" vs. "early CTO" interviews.
If that's the case, then the onus is on the founder as much as me to prove their worthiness. I've inherited too many dumpster fires in my career to implicitly trust the word of non-technical co-founders.
- get started on my own without them
- if I was lucky enough to find someone I actually wanted to partner with, I'd make sure we'd be able & willing to own code both of us had written
- not get too attached to my pre-founder code (probably a good idea in general)
- offer them a nominal hourly rate for a week or two just to validate skills & compatibility while they decide for themselves if they really wanna do a startup with me
- when they fully committed, offer them the same comp package I offered myself, including number of shares
- hope it all works out!