Sorry, I stepped away for a bit myself. And I see you're away too now. So I'll tell you a little bit of what I think. I encourage you to read it all carefully and then reply.
Firstly, this is complicated stuff, and there's a lot on the table. You said she's getting ready to break. She can't get through this without professional help from a lawyer. I know lawyers are expensive, and if husband is pressuring her to sign the agreement because he guarantees her it's fair and this way they can avoid court and expensive lawyers, he's simply trying to bully her into agreeing to what he wants. That's not always the case, but if he's threatened her with selling the house if she doesn't agree to his proposal, that's no agreement at all. How does she know if the agreement is fair or reasonable unless she gets advice on it? Husband is trying to bully her, I guarantee it. Do everything in your power to persuade her that his threat to sell the house is not only an empty threat, but that it's evidence that she absolutely needs legal counsel.
It's normal to assume that all of this can and should be able to resolved in one fell swoop. And if the spouses are well informed and have legal advice and negotiate in good faith and make full disclosure, then it can be done this way. However your daughter isn't well informed, isn't getting good legal advice, and has a spouse who is making all sorts of demands. She needs a lawyer or else she, and more importantly the children, will get screwed. Period.
Let's talk about child support since you started with that topic. If the children are primarily resident with the mother, then father pays child support based on his income, and contributes towards special and extraordinary expenses on top of that. If dad earns $42,700 and owes for two children then his child support will be $600 per month. That's what a court will order, and there are very few ways to deviate from that amount. Here are some of those ways:
1. The parties agree in writing that dad will pay less (or more) than the guideline amount for a good reason, such as dad's costs of exercising access are high, or a child has a special diet and needs expensive food while visiting.
2. Dad has taken on more than his share of the family debt upon separation, and mom is paying him back for covering her portion of his debt by accepting less child support than normal.
3. Dad's support payments would cause him undue hardship, like if mom is remarried to a multimillionaire and she literally doesn't need the guideline support from dad.
4. Dad is paying more than his share of the child's extraordinary or special expenses.
5. Dad has the children 40% of time or more, leading to a presumption of "shared custody" and a child support setoff situation where each spouse pays the other full guideline child support.
Often the support payor will want shared custody or approximately 50/50 time sharing of the children because they assume that they'll pay no support (not true) or far less support (sometimes true). So, let's look at what dad wants. If he gets the kids every second weekend, that's 4 days per month (maybe more if it's a Friday to Monday morning), and he wants another 8 days. That's 12 days per month. Throw in a little time here and there for Christmas or stat holidays, and guess what? He's got them 40% of the time. I guarantee you that this is why he says he wants them for an 8 day stretch per month.
So if he does get the kids this much, he'll claim that he pays no support. That's not true, it would be done by way of a setoff as I said. Dad's $600 per month would be set off by mom's $423 per month. That's what she'd owe him under the guidelines for two kids on her income of $29,000. So he's owe her $177 per month in child support, and he'd get half of the child tax credit, dependent deduction from taxable income, etc.. This is why dad is saying she can have the house if she buys out his share; he doesn't care if she has the house as long as he has the kids 40%.
That's just an example of how complicated it can get and why she absolutely needs a lawyer of her own. If he's being a jackass, then she can take him to court and get an order for exclusive possession of the house. I assume that the kids would rather stay in that house with mom full time post separation.
There's lots more to talk about, but I want to send this now before you leave. Read it to your daughter. SHE MUST GET HERSELF A LAWYER!
Please reply to me when you have time. If I've answered you, I'd appreciate a positive service rating please.
I hope you're reading what I just wrote. Perhaps you or your daughter should get a subscription to this site so you can ask a certain number of questions per month for a flat monthly fee. She still needs a lawyer, but she could do with this site's service too. (This site can't give the legal advice she's looking for, she still needs a lawyer.)
So, she should tell her husband to go pound salt, he can't sell the house on his own, and she's getting a lawyer to help her with the agreement. He can't stop her from doing that, and the more he objects the more you know why: the agreement right now is in his favour.
(Also, child support can and often does continue past high school, if the children are disabled or are enrolled in and attending a full time post secondary educational program, so his cutoff date is also both arbitrary and in his favour)
Ulysses