you say not needed for the plot, then state how they save the heroes. and then you seem to forget how they make the final transmission possible.
IIRC the only time they’re relevant to the plot after saving the heroes is when they made the final transmission possible. So in a Chirrut and Baze-less version of Rogue One, either that plot element would have been removed, or another character would have made the transmission possible.
Again, I repeat: I have no problems with the characters themselves, my problem is how underused and “irrelevant” they are. If Rogue One were lighthearted like Star Wars, it wouldn’t be a problem for me.