okay I couldn't remember if MC knew the letters got switched up or not. Him not being aware makes this all make sense now.
Only issue is the TL using concrete pronouns on pg.3 ("I wanted to get closer to her") which does make who he's talking about unambiguous. Not sure if that's how it is in the raws, and it's simply a matter of MC mumbling that sentence and Ren-kun not hearing him properly, or something.
Otherwise, it all would remain very ambiguous and the gag of "misunderstanding" would be consistent.
Not a very novel concept as far as creating narrative conflict, but throwing in a bit of mistaken BL, when in fact both of those boys are interested in the same girl (if in slightly different ways), does make it funnier.