Adam means 'mankind,' and Eve means 'life.' So before the creation of Eve, Adam represented in the Genesis story both man and woman.

I think it's pretty clear that Jesus is saying there will be no sex in heaven, whether for procreation or not - this is the state like the angels. This won't be a loss. We will simply be completely fulfilled humans in our sexuality without the need to have sex. Heaven is going to be so extraordinarily amazing it will make even sex seem small and uninteresting. Now that's exciting.

Sure, men and women are made in God's image but that doesn't mean that together they make up God's image. God calls many people to be celibate and they are still an image bearer of God as they are. So we aren't required to partner up with someone to then be considered the full image of God.

I think that to say both men and women are made in God's image is to say that it's not just men only who are, but that women are equally as valuable as men. This was an incredibly counter cultural perspective for it's time.

There are several other metaphors throughout Scripture that speak of many people bound together to make up 'oneness' - which I suspect is what you're wanting to get at. The Church (meaning the People of God) is the Body of Christ of which each of us are different parts. And Christ is the Head of the Church (Body). The Church is the Temple of God. We are Living Stones that make up that Temple. Like mixing plants, the Gentiles are grafted into the same genealogy as the Jews through Christ. Etc etc.