What if, before every dev stream or leading up to it, people can post questions they’re curious about in a thread or discussion? Mods could vet them to see if they should be included. Then, during the dev stream, Vedal could go through them and see if he wants to answer some.
So, basically, add a small segment to the dev stream where he answers questions from viewers. Viewers then won't have the spam in the chat over and over.