see told you the husband of the sister was a nice guy, they just had to rush the wedding for the pregnancy and save face since japanese are like that. I'm sure they were going to marry anyway.
If her mother wasn't like "that" then she was making the right choice, twins still somewhat like their mother since they don't know much about what happend but hotaka does and she was sure that it would've happend again. Great for wahei and be the selfish adult.
I thought the power didn't work with her since she was in love with that clown. Just like inuma girlfriend and biker girl they care about rokudou but their feelings are others now, and now they say that his power is getting weaker, seems working fine to me... unless is only with ranna.
zagan can have a harem but doesn't want it, I believe nephy would accept holy knight but I think is better without it, sometimes is better without a harem like in this manga.