You can do it -- a few companies in my batch (W12) have done it and we have a large YC international community to help answer all your visa questions. Answering your first 2 questions (briefly):

1. Don't know -- my thoughts would be it depends on customers (if it is worldwide/local to India, team location etc.)

2. Yes, it is possible through H1b/O1 visa (a number of founders have done/doing it)

* Would recommend focusing on the application and interview -- the YC team,international YC founders community and recommended immigration law firms will help you once you are in...