I was thinking about how, with the new context of s4 ep5, it makes way less sense for Bot to want to play Mephone in the ep1 play (also known as Mephone Slander: the Musical)
The out-of-universe reason for Bot playing him is probably to show how they parallel each other as characters, especially since there's lines like,
"What kind of a monster creates a whole new person, just to make them do his bidding?"
and also the part where Bot says,
"You could quit your job, raise a family, quit that family, and get a new job!" which likely means something since Fan, Test Tube, and Bot are really the only family in the show. I think it's referencing both Mephone leaving s2 to make s3, and Fan creating Bot and then immediately leaving them to go back to the hotel after being eliminated
Anyway, when ep1 was the most recent episode, you could assume that maybe Bot didn't see Mephone as their friend anymore or didn't like him anymore after finding out he created all the contestants (and technically also them), and that's why they were fine with being in the play, but this gets proven wrong in ep5
In the newest episode, they tell Bow that they miss Mephone, regretting that they never got to say goodbye to him. They're the only person who's really been shown to miss him, other than Cammy, who mostly misses their idealized version of him and not the real him. Bot also says,
"I guess I'm feeling... disconnected, from everyone lately", which is them talking about not being there for the finale, and their opinion on the game, but is also about them feeling alone in missing Mephone. Bot also says,
"Like, why did they send MePhone away if they were just gonna do their own game anyway?"
Unlike how all the others seem to feel, they're suggesting that MePhone left not because he wanted to get a new start somewhere else, but because he felt pressured to leave by the contestants, thinking that they wouldn't accept him. Bot could also believe that the others literally sent him away, since they weren't there to actually know for sure what happened. They also haven't discussed feeling this way with anyone except Bow at this point in the season
(On a side note, it's interesting how Bow looks surprised when Bot says this, like even though she agrees with them about the game, she wasn't expecting them to feel this strongly about how MePhone was treated)
Overall, we know that Bot misses MePhone and still sees him as their friend, they feel like he was treated too harshly in the past and should have been given a second chance, and they believe that they're alone in thinking these things and that no one else, even their family, would understand
With all of this, it really doesn't make sense how Bot would be okay with portraying a demonized version of MePhone in the play, or how they would even want anything to do with it at all. Even though it was still the first episode, the writers would have had the things from ep5 in mind when writing Bot in ep1. The explanation that makes the most sense would be someone else, maybe Cabby since she seemed to be in charge of the play, asking Bot to play the role and them saying yes since they don't want to disappoint, since that's also what happened with them co-hosting the game