[snarf21]

This is the most obvious issue. They don't have a great team. At best, they have potential great team members. A great team implies applying talent and a vision to solving problems. They can't come up with a problem to try to tackle. Most people here on HN have 7 problems they'd love to work on but don't have the time or resources. I also think it is a big challenge to pick a problem you don't understand or have no background knowledge about.

I'd suggest picking an industry with known inefficiencies (health care, education, etc.) and have all three go work at three different companies in that space for a year. Then come back and I'm sure lack of ideas won't be the issue.

Remember, ideas are almost worthless and at best merely a head start. Execution is EVERYTHING.