About the gender bender issue, it was about the last couple. The uke was intentionally designed to look, and dress like a girl.
About the male pregnancy, some people might have mistook the last chapter, where the first(=main) couple were looking after the baby.
I wish I could help you with your last question, but unfortunatelly I don't have enough information to help you any further, sorry.
Hanamuko-san is sequel to the story of the second couple that got married :)
i think aoi could be somewhat considered gender bender. I mean, he had a super girly face... maybe?
I read that in this manga there was a) genderbender and b) male pregnancy
I didn't see any of that. I may have just missed that though. I don't get it, and how is Hanamuko-san the sequel?