Everything I'm about to say pertains to my own perspective and experiences on SubaHibi, so this should all be taken with a grain of salt.
Here are my answers to you on those points you bring up as "A" and "B" (and "C" for the question on Zakuro).
which is by default given to every "complete" existence when born. So in a sense, it's saying that people who are born but end up broken can still grab an opportunity to be reborn, for all we have is our internal world. And of course, SubaHibi also shows exactly what causes people to break themselves, in not accepting their existence, and consequently, their own birth into this world. If you look at someone who's mentally unstable and/or hospitalized, your exterior viewpoint (the initial impression) immediately sees a person who could never be happy. SubaHibi is trying to show the audience the inside of such a person and that they can indeed find their own happiness again.")
It's most definitely not as complicated as I make it sound with this sea of words, so I recommend to take a second or perhaps third look at everything. (Especially