Upvote:3
No, you don't need a visa if you have confirmed onward tickets and your stay is less than 24 hours.
Yes, in your specific case you need a visa. Typically you wouldn't if your layover is less than 8 hours (provided you have confirmed onward tickets of course)
Yes, you need a visa but you can get one on arrival for 30 days
Emirates airlines has an IATA-Timatic based web app to figure this stuff out