3. If you're an exec earning $300k at big corp, you are not going to get $300k at a startup, because the startup obviously does not have the revenue or cash of big corp. Ditto for an engineer earning $150k at a tech company. But who said anything about a pittance? It's up to you to set your own salary. You can still pay yourself $100k/year, if that's necessary. The larger point of raising money is not just for paying yourself, but it's for hiring other people.
4. http://ycombinator.com/ycvc.html I made a correction to my post: the amount is now $80k, which is still good considering the assumption is that the money only holds you over until you raise money after Demo Day (say, 6 months). The link is a bit outdated because YC uses SAFEs now. But the notes had no discount and no cap, which are the best possible terms for notes, and that carries over to SAFEs. YC is brokering these. They have their own separate terms, but the terms are available publicly online and are the same for every YC company.