Ask HN: Interviewing a business co-founder

What do you look for? How do you tell if they have it? For me: The basics: -passion/dedication with a direction -15 to 20 years of industry-specific knowledge/experience -long term vision -work ethic -appreciation for other processes (tech, design, finance) But I'm having a hard time deciding if they need anything more: -should they have expertise in one of finance/marketing/sales? -PM experience? -what specific questions would you ask them? Is it same as hiring a PM as long as everything else works? I haven't come across many that fit even the basic criteria but I'd like to be ready the next time I do, all help is very much appreciated.