So I actually have some more comments on this, which upsets me because I should have just waited to finish the chapter being making the original post.
However it’s better late than never.
So he does actually use honorifics for Kris, Susie, and Ralsei. Each of them get appointed ちゃん (-chan) by Tenna. Usually people say that -chan is used for girls, but it’s actually used in a variety of circumstances. In general it can be used affectionately for someone younger than the user, and is sometimes like a “cute” nickname. I would argue in this case, it is Tenna doting on the three, however he doesn’t do this consistently. Its strategic.
When Susie talks to him in private (where Kris and Ralsei get to eavesdrop), he uses -chan with her. He specifically chose to use an affectionate term for her here, because he was worried about being caught. So he turns to his people-pleasing and scrambles to change the subject.
He also uses -chan for Kris but I cannot for the life of me remember when this happens. I do remember it being in another instance of him being strategic with his words, but I might have to update this post again to complete this explanation.
Ralsei has -chan used for him when Tenna is losing it right before bringing up the doom board. It’s during the “RALSEI MY BOY!” Segment. This fits for reasons you can extrapolate from above, but he is both desperate AND using softer language, which gives a nice and dissonant vibe to the way he’s acting in that scene overall.
As for additional observations, he uses キミたち (kimitachi) to refer to the three of them.
Kimitachi is yet another soft expression, used in familiar settings and the like. It’s a term that means “you guys” or something similar. It’s a term usually used by men, too. Compare this to the common (less familial): みんなさん (minnasan) used to say “everyone.” I believe he uses minnasan somewhere in the game to refer to his audience, however I don’t have a screenshot for it.
TLDR: Tenna uses a lot of affectionate and warm terms. How you interpret the reasoning behind this tender language is up to you. He uses soft terms for all three of the main crew, and continues to use it even when he is losing his mind (dare I say he uses affectionate terms MORE post-doomboard).
I’ll make another post later about his behavior and language during the TV World part of Ch.3, but that’s about all I got for what terms he uses for other people.
Oh and one last thing. He uses おれ (ore) as his pronoun.