For Indiviual stars (I want to submit a time for Cosmic Cove Galaxy, Twin Falls Hideaway) can you submit a screenshot of your time at the star selection screen for proof?

Hey Flashy, I don't know the rules specifically for their board but there's a few places to look to get the answers you're looking for. The general rule I've seen within communities is that proof only starts to become important as you get closer/get the WR on games where it may be harder to record, but it's different for each:

http://www.speedrun.com/smgalaxy2 (it looks like in the main categories they have someone in 5th that was accepted without proof, but asking in the forums there may help)

https://discord.gg/0dEhnBwKhhgt1nWe (Discord server for Galaxy speedruns, should try asking there)

Best of luck with your runs o/

Thanks for the help :)