I like this — but it would not have to be "live" chat. Most chat systems these days are asynchronous... I would still think there are lots of benefits being able to leave messages and ask for clarifications around each question being asked / answered.

Perhaps I am confusing this with a feature to leave text and audio "comments" for each questions?

This would also improve the "back and forth" aspect.

This one should be optional. Imagine I send an invitation link to a guest and I am not available, so the guest ask a question but I am not able to answer...Bad user experience.