Here are the questions I would ask: Are they actively turning down funding or have they just decided not to seek it? If the former, who have they turned down?

Here are the questions I would ask: Are they actively turning down funding or have they just decided not to seek it? If the former, who have they turned down? How much angel capital do they have? What's their burn rate and runway? Have any of the principals started companies in the past? When are they going to add benefits? Those things will help you assess stability.