I've got a question about the Japanese version if you don't mind (saw you translate few lines while I don't understand anything of it); in chapter 5 when Monokuma confirmed Ouma wasn't the mastermind in English version did he confirm he wasn't mastermind or ringleader in Japanese one?
This one's no problem, though uh, heads up for future reference that I do not know Japanese very well and severely out of practice so the extent of it is picking out some interesting things and cross-referencing
With that said, let's get the original:
This little word here - 首謀者 - is the one meaning 'ringleader'. Taking this in context, he is saying ‘I’m not being controlled by Ouma-kun, which also means [I am assuming from this that だって can either be a ‘because’ or a ‘therefore’, two mildly different impressions there?], he’s not the ringleader’.
There are a couple of things wrong with his assertion, however:
Early on when Monokuma talks about ‘the mastermind controlling him’ (Chapter 1), he not only distinguishes this controller with a separate word, he also talks about the ringleader as separate to the controller, so per his own words the ringleader would not even be controlling him in that sense
Monokuma states afterward that Ouma’s scheme ‘began after learning the truth via the card key’ (from Chapter 4), neglecting the message in the courtyard which was first altered back in Chapter 3, and seen as altered again right before he even gave out the card key as a motive. At this point he’s either forgetting or... omitting something (possibly, about the nature of the message...), but either way his words now are not completely reliable
There’s also the issue that he wouldn’t outright confirm the identity of the ringleader if it didn’t suit him- his second statement that he ‘never once said anything about Ouma being the ringleader', doesn’t say anything about the validity of that because why would he tell them if that’s true or not? So yeah, he says what he says, but it’s a bit sketchy...