How do I file and/or negotiate w/mediator for kids/house

[spritom]

Wondering if there's a "recommended way" to go about filing or negotiating w/mediator for custody/house.  Well, the material things are secondary, but they do add up.  If we negotiate out of an item I really like and chalk up the monetary value, so be it, but #1 for me is the kids.  I feel the 3 girls would have a much more peaceful/stable home w/me than STBX.  I've always felt that, but was thinking that we'd negotiate and I'd end up w/some parenting time/every other weekend thing.  But not so much now.  Perhaps a fallback plan to 50/50.

Atty is working up papers now (it's taking a few days, not sure if that's normal).  Meanwhile, BP-STBX and I went to an initial consult with a Mediator.  Certainly a mediation sounds like a much better way to go than court.  STBX in the past has said she "gets the house" and "gets the kids," but has given me very little other info.  I've scribbled up examples of what it would look like w/her in house and me w/130+ days of parenting time and talked to her about it...no real response from her.  Plus on the mediation thing, seems like I'm the primary mover on it...I call them, we go to an initial consult, I give my opinion to STBX afterward whether I like them or not...she gives me...nada.  So we haven't settled on a mediator yet.

So on the backside, I've got an atty drawing up papers to file and start the clock for her (AZ is 20 days response, though courts often float that time out from what I hear).  I'm writing it for me to live in our house w/the kids and she with about 130 days worth of parenting time.  Our wages are near equal w/mine a tad higher, so me w/kids shows on child support chart of her paying about $60, and her w/kids show around $400.  She was SAHM until 2 weeks ago..she just got a good full time job.

Expected response from STBX:
* on the subject of me filing = 2-stage ballistic launch
* on the subject of me stating for me to be in house w/daughters = 3-stage ballistic launch

Both of us live in the house now.  I've heard of temporary orders for use of house and temp custody, not sure how they work.  Not interested in falsely accusing/filing stuff (seen it happen though).  STBX is big on the arguing/lying/emotional abuse thing, but on the BP side, she slanders me to all that will hear with false accusations (sometimes she'll tell the truth, but switch the names).  

Mother-in-law (MIL) lived in house for 6 months and now down the road.  MIL was there for many of STBX's antics, but appears to be 100% blind to them even when occured right in front of her.

Due to Borderline-type behaviors she's exhibited, I'm thinking there's nothing to do, but just go through it.