Do you have a lawyer? Have you ever had a lawyer look at any of these contracts? That is where I would start.
No, but I'm looking for a law firm that has experience with funded startups
I'd look at the tier 5 and 6 firms, they may be more interested to work for individuals. If they won't act, ask for suggestions as to who might. They may know of freelance lawyers who could be a good fit for you, for example.