I've heard that you have to have the bed room in order to have a family moove in with you. This seems so... pointless, as I allready have bedrooms in the mainhall that would work well for a wife, child, and steward. Any one know?

No, you don't. To adopt kids without the bedroom wing, you need the two beds and dresser built in the upper level of the Main Hall. Your spouse can sleep on the large bed that you build on the other side of that floor. I'm surprised this bit of misinformation is still floating around after all this time.

That's right, and don't forget the dresser, you have to have it, it goes against the wall between the two single beds. It's considered the 'kids chest'. That's where they will put their stuff. If you forget the dresser the game won't let you adopt, saying you have no room.

Indeed, people need to know that none of the wings are "required" for anything, you can still adopt without the bedroom and you can still do alchemy and enchanting without the towers, all those things are also in the main hall. Customizing your wings are more for aesthetic reasons so don't feel like your forced to get any of them, choose the ones you want, not the ones you think you need.

i like geting the bedroom wing just for the little porch myself

I must have forgot the upstairs dresser maybe.
I tried to get them to move in to my house, I had the beds upstairs and downstairs and at least 1 set of chests for them downstairs.
Couldn't get the option for them to move in, I sent them to whiterun instead.

So I head to whiterun to find them and I see my wife in there with them even though she should be at the big house I want the kids to move to.
So I ask her to move back and the kids go as well.