Grouping by actor is currently not possible AFAIK (would like that too, plus by director).
1. Yes (top of home screen or library menu)
2. No.
3. Yes (library menu or library settings)
4. The top of the home screen by default shows items you are currently watching and most recently added items (can be configured in the settings under "up next"). This is also shown on the ATV's top shelf if the Infuse icon is in the top row and selected, so you can jump e.g. to the next TV episode right from the ATV home screen.
5. Currently not possible. But you can add your own favorites to the home screen, including items from the library menu and categories.
Plex does that on the central media server. I was just pointing out that Infuse can track watched status across devices even though it does not use a central library.
This is all getting a bit off topic. I suggest you use the
Infuse thread if you have more questions (there is a Firecore representative there who answers questions and is interested in user feedback).