prep for mediation does everything come out?

Hi Guys. I have been to lone mediation session stbx is due in this thursday. I suspect we will both be in pretty soon after that. After she confessed to me last sept, situation we are in now is, I am in rented and FMH is up for sale with an offer on, I would think that she is going to have to come clean in mediation as to what her plan is, before I can agree on a split of equity, which is around £100K on the house. More or less everything else we have sorted, I feel there is a bit of ground rule stuff to be made clear about kids contact as generally she has her head in the sand at the moment, thinks things and maybe me, be will just go away.

So my question is, IF her parents are going to chuck a lump of money in to enable her to buy this other house, which she has led me to believe, (other house up for £129K, even if she gets £60K from fhm she wont work is on benefits with the young kids how will she fund it?) is it fair for me to be unable to agree to division of house unless I know what she plans, thing is, if the Consent Order is not passed, (which is my understanding on the process of a mediation) house could end up in a mesher order anyhow?
I hope I have been clear on the details of the situation so you can answer.
Also, what guarenttee is there on a mesher order that you get your money at such time as it becomes payable?