This is a quite old thread, but on the point of streams:
Streams can still be allowed while limiting the ability of stream snipers by enforcing a stream delay. It doesn't have to be huge -- about a 30 second delay would probably do the trick. I'd personally prefer it to be longer (around 1-2 minutes), but 30 seconds allows the streamer to still be able to easily interact with their chat for an entertaining stream without the chat being too far behind.
Also, I absolutely agree with the idea of co-op being limited to 3 teammates which are not on your friends list (although I would encourage an exception -- teammates may be added to the friends list for the beginner TTC task, but must be deleted immediately after the task is turned in).
Might just be crazy enough for a run for like this. I'm already sleep-deprived anyway.