What I find interesting though, is that OP went from interning at a YC company, to founding one. Would love to learn more about that process, and the visa situation throughout, since I don't think you can be founding companies and getting investment on a J1 visa.

I interned with a big company this summer that had an established J1 process (Microsoft), so didn't have to deal with a lot of these hassles - they organised the J1 visa and sent me SEVIS papers that I simply took to the embassy in London, and got my visa approved after a 2 minute interview. They organise housing and give you a rental car or bike based on your preference. The biggest worry for me was that they may incorrectly apply the 'home country physical presence' requirement, since India lists every single possible skill as wanted. Still, it's interesting to learn that the process is still doable for small startups without the same resources, in case I need it in the future.