Internet bandwidth!
For a 1080p/i (HD) stream the bandwidth you'll need is between about 4mbps and 6mbps upstream. I.e. from your setup to the streaming platform you're using
If there's participation, engage with social networks and find ways to curate your audiences response - reboot the stream 5m or a day later to get to the next bit with their input
Best bang for buck for a setup such as this would be the new ATEM mini ($300) or the ATEM Television Studio HD ($999)
It often comes as a surprise that most laptops simply don't have that ability off the shelf
This doesn't have to be as onerous or confusing as it sounds. They're just jigsaw pieces that need to be plugged together
Built in camera audio is often a bit shaky, and will more than likely pick up camera operator noises (changing zoom, moving the tripod), or if its too close to the tech box the sounds of the technicians swearing
At the very least (and assuming you're end-on in a theatre space) a shotgun mic pointing at the stage on a stand away from other people is a go-to solution