This is a great post, I think a few other things that make a company look credible are these:
1. When they have a blog that has weekly updates on what the team is doing or how the ICO is doing, full transparency for their token holders or potential investors
2. When you can see them actively answering questions on websites that you can make comments on
3. Something mentioned in their white paper or their website that says whether they are a utility or security token, and if security, how they will handle SEC regulations