Within 48 hours of the draw for winners, non-winners and prize sponsors. Send the results announcement to your full list 48 to 72 hours after the draw, and thank volunteers within a week.
Yes. They are the majority of your list and they funded the result. A warm thank you that shows what their tickets achieved is the most reliable way to bring them back next time.
Generally no. A raffle ticket buys a chance to win, so it is usually not treated as a tax-deductible donation. Thank buyers warmly, but avoid calling a ticket purchase a donation, and check the rules that apply to your organization before offering any receipt.