Thank you for setting up office hour and discussion channel. I think it would be super useful to have some guideline/documentation, even unofficial one, before the office hour, so that people can read them first and be more prepared when participating 
Topics I immediately think of:
- email filters
- Hand-on experience dealing with the noisy
https://github.com/notifications - blocking reviewers, especially libc++/libc++abi/libunwind (Input Needed: Teams for Pull Request Subscriptions - #14 by philnik)
pr-subscribers-*auto approver (Input Needed: Teams for Pull Request Subscriptions - #61 by mehdi_amini)- How to create new teams? (Input Needed: Teams for Pull Request Subscriptions - #48 by ChuanqiXu)
- moving reviews from reviews.llvm.org to GitHub
- How to comment on old patches on reviews.llvm.org
- New pre-commit bots
- Quality of squashed commit messages