Welcome to our forum.
You might want to do a search, or tag search, for "kids," or "children." It should lead you to a number of insights about having kids in a poly household. The search menu is on the top bar of this page (a bit to the right).
It sounds like you guys have a loving bunch, with a good chance of making this moving-in-together thing work. Just be prepared for it to be a bumpy process in the beginning. You have to figure out what works for each of you. Sometimes privacy can be an issue. Will people have "caves" they can "retreat" to?
No kids myself, so I can't advise much, but maybe others will chime in here? If not, try starting your own thread under "Poly Relationships Corner
Good luck (and good love) with all the exciting changes on the horizon.