I love your “roll initiative for monsters” button! For your encounter flipping, I would recommend having each encounter in a section, and then using a Table of contents type approach.
For tracking player damage, I would have one table with players, damage, armor class, skills, and a dropdown for states (poisoned, etc.). Then, I would make a view of that table in each encounter page. That way it will always be there for you.
What’s the setup on your roll for initiative button by the way?