I felt the characters were sufficiently developed for their various purposes within the movie. We spend as much time with them as we do LUKE/LEIA/HAN in ANH.
What exactly do we learn about Chirrut Îmwe, Baze and Bodhi Rook other than the templates for their characters? Not much…Can’t say the same for Luke, Han, Leia, Rey, Finn and Kylo Ren.
What do we learn about Chewbacca and R2D2 in ANH? We don’t need to have some sort of comprehensive emotional arc for each character necessarily.
If Chewie and R2 were “normal” characters your comparison would be solid but there is a language barrier that stops characters like that from being developed properly. A better comparison would be Lando but even he in ESB has more going on under the hood than both Baze and Chirrut.
Bodhi is constantly terrified - but then does something brave and feels fulfilled - almost like a watered down Han I guess (selfish - selfless).
More like a watered down Finn. Han is motivated by pure selfishness while Finn and Bodhi are motivated by fear.