Indeed they can and it is very annoying having to sign up all the time, remember new pw and go through a process Arrgh!!
I have tow email accounts one for business, family and friends and one for general rubbish. Stuff I have to sign up to generally goes on the second acc or if it's a more permenent long term interest then I'll use the main one.
As regards Twitch you don't have to do anything to watch the channel but you do have to register to post questions and comments to a live "chat room" running down the right-hand side of the screen. Personally I find chat rooms move too fast for me to catch up on and respond to so I'll probably just ignore it. However if we want to reach out to a wider audience it may have to be watched.
What would be easier for me would be if a thread was set up here (or facebook, I'll set up an event page) that people could post questions to.
As regards people contributing we'll have to see how this works. I've seen twitch channels with several people chatting at the same time with their camera feeds overlayed but I'm not sure if this is done automatically or they are using a live video editor. For the start it will just be me waffling along as I create a couple of scenes and chat about the process.
Suggestions of scene topic and waffle topic greatly recieved