I am finding waitlist tickets from SEA-SIN-India and I have few questions

1. Is it possible to add a segment from my hometown (midwest usa) to SEA on Alaska or United Airlines? How? Would there be extra point for that?
2. How long it takes to clear waitlist? Would that always clear - I am more than 6 months away from flight date.
3. Can Domestic segment be on waitlist?

Thanks in advance.