There are plenty of amazing games with no HUD whatsoever. First thing that comes to mind is Journey it literally has no HUD element, most games from thatgamecompany are minimal like that.
Also games by Josef Fares have almost no HUD, Brothers and the Hazelight Studios games similarly don't rely on the HUD much.
The panel with young Kizaru, Vegapunk and Sentomaru was very cute. I really wonder if Kizaru will still be "just following orders" by the end of the series.
You're probably right considering they announced most of the cast for the characters in Season 1 but Johnny and Yosaku weren't in the announcements iirc