overall i thought it was really well executed.
If i had to give personal design opinion i would say i would follow an ethos that keeps the tutorial graphics away from the players, specifically their faces to avoid covering them. I would say from the screenshots that the bottom third of of any given shot is safe real-estate to work in.
If you wanted to go into realm of fantasy i would suggest having a prominent link at bottom of screen / below the vod / spammed in chat that goes to a itmejp site page thats live tracking the four physical character sheets , showing all their current stats and abilities. with tabs for cast info , patreon etc.
And while we are on fantasy an ipad for adam and a big ole 30 inch touch screen laying on the table running roll 20 for the purpose of using dynamic maps, trackign character movement ranges etc etc (but not rolling dice). Thats not so much your department though. XD