For point 1, I assume the original meant the usual "hierarchy" the Japanese oh so much love in everything. Not sure about any other specific terms either, since I haven't been paying much attention myself.
The cave is just their base of operations. You can call it whatever you want, or whatever...
these guys gonna be ending in weird situations for three years anyway, so don't worry sensei, take your time.
On a more serious note, jk gal best girl, but I guess you can't have everything from life...
I mean, realizing her wrongdoings is a small step forward, but, as things stand, their relationship is definitely dead. For good.
Now, can we get Makoto to meet the other protagonist?
she's probably pretending to work with the brother: all the things she said in the past couple chapters would make no sense otherwise (or perhaps she's just that great of an actor, who knows)
people talking about NTR when they don't even know what NTR is: the literal translation is "to steal under one's nose" (netorare), but it refers to when you "steal" a person in an already established relationship. The girl didn't even know who this "hero" was until now, so where the hell are you...
I'm not sure what to think: on one side, both her mother and grandma have been uncooperative since the beginning and nothing seemed to get through them, so her mother having some enlightenment out of the blue at the end feels like the only way things could have changed/been resolved; on the...