In-person True Dungeon events have always required you to check in 10 minutes before the scheduled time in order to create a character, and hang around after finishing the dungeon for XP and prize draws. As the virtual event is not doing any of that, does that mean it will stay within the ticketed hour? They changed their slots and I'm trying to see whether it still fits into my schedule.

Virtual True Dungeon sticks much closer to actual times.
You get into your time slot general at start time, sometimes a minute before. The coaching time is much easier, as stats are all set in the apps. Mostly it questions about how the app works or things like that. They do visually check treasure enhancers, and set difficulty.
At the end there is epilogue, but that is mostly making sure everyones treasure totals are correct. You do get some time for feedback or chatting if you want, but no more than 12 minutes worth, as the Epilogue Coach has another group to do by then. Many times folks scoot very quickly.
Its a blast!