Most hybrid events are an in-person event with a camera pointed at it. The online audience can tell, and they leave.
Give the stream its own owner
Someone whose entire job is the online experience: the feed, the chat, the questions, the moment the slides stop advancing. If that job is shared with a stage role, the stream loses every time there is a conflict.
Bandwidth is a hard constraint
Test the upload speed at the venue, at the time of day you will broadcast, with the room full of phones competing for the same network. Have a mobile fallback on a different carrier.
Two cameras minimum
One wide, one on the speaker. A single locked-off wide shot is the fastest way to make an hour feel like three.
Price the two tickets differently
An online ticket is not a discounted physical ticket, it is a different product. Price it on what it delivers: access, replay, maybe the slides. Do not let it undercut the room.
Audio matters more than video
An audience will tolerate a soft picture for an hour. They will leave within two minutes of bad sound. Take the feed from the sound desk rather than the camera's on-board microphone, and have someone monitor it on headphones for the whole broadcast.
Plan for the slides
Whatever is on the screen in the room needs to reach the stream legibly. A camera pointed at a projector never works. Capture the presentation feed directly and cut to it.
Decide what happens to the recording
Replay access is often the main reason someone buys an online ticket. Say clearly whether it is included, for how long, and when it will arrive. Vagueness here generates more support messages than anything else.
Bring the online audience into the room
Read online questions aloud from the stage. Name the people asking. The moment the in-person audience hears that there are people watching, the stream stops being an afterthought for everyone.