So, having put it out to the community at large, I was very pleased to have gotten a response to our request to help find a house mate! We were referred in a single dad with a daughter in the same age range with mine, who is in our age range, and is both poly and kinky. Thank you to Ms A!
This looks like a pretty good fit! He was over last week, loved the space, put the deposit down and signed the rental agreement. We all had dinner together, including his daughter's mom, and the kids got to scope each other out as well. The dogs were even relatively well-behaved.
It's going to be another new situation to be sharing space with someone that is still a relative stranger, but the basics all seem to be in place, and it was such a relief to be looking at this scenario with someone who is relatively versed in basics of poly and kink, who isn't attaching negative moral judgements to multiple partners, marks, the chains that hang in our laundry room (which are actually for hanging laundry, but look really kinky), and seems interested in possibly participating in community stuff etcetera.
We have a month before they move in, and I think all of us around here can use the time and space to take many deep breaths, establish a new routine, and become more comfortable with different kinds of freedoms, like weekends that are largely kid-free. The kiddo starts school next week, and I think the additional structure will help her to continue to acclimate to the changes in family life. Getting used to another child around will be interesting for all of us, but it looks like the kids are going to get along pretty well, especially on a part-time basis.
While I'm not totally certain how this is all going to shake down, I'm pleased that so many things are falling into place as desired. One step at a time, one foot in front of the next.