This will probably not happen, but in the rare case that the players outnumber the blooks, Blooket will provide plain color blooks for the remaining players to join.
No, Facebook just has a space limitation that they handle by adding "and X more." If you click on the names listed, you will be able to see that extra...
You may try, but I do not think so. I never saw an option. Try emailing the duo maker (the app store should have that information/help center) and ask.
Most YouTubers don't use the standard PS4 recording software. They tend to use an Elgato Game Capture Card or Black Magic Intensity -- something along those lines. They are very...