Contact your insurance agent and/or insurance company at once. Your auto insurance policy should provide you with a defense attorney in connection with any claims asserted against you and your daughter, and this attorney can explain the answers to your questions in detail.
Best wishes to you.
No attorney-client relatonship is created in responding to this question, and advice provided is based solely on very limited facts presented, and therefore may not be correct. You are advised that it is always best to contact a competent and experienced with the practice of law in the county in which you reside, particularly as it relates to family law, child support, custody and visitation (a/k/a "parenting time") issues, including 209A abuse-prevention restraining orders (a/k/a "ROs" in legal-speak), regarding un-emancipated children, under the age of 22.
If the attorney for the pedestrian does not accept a settlement and the case ever goes to trial remember that the plaintiff must prove fault before anything is owed. Your insurance company's defense counsel needs to answers your questions and concerns. Also it will probably be worth it to at least consult with a local private personal; injury/defense attorney to answers your questions & to assist in protecting your family's assets from any potential verdict.
This is not intended to be legal advise or as legal representation. I am a California personal injury attorney . Be aware that every state has its own statute of limitations; and statutes & case laws that govern the handling of these matters.
Your insurance company owes you a defense. The lawyer retained by your carrier to defend you and your daughter can also defend by claiming the brake failure and the fault of the seller to inform you of a problem with the car. Don't take this on alone. Make sure that you contact your carrier.
Your auto insurer should be required to hire a lawyer for your daughter, who is supposed to represent her interests. Your auto insurer is also supposed to cover the cost of defending the lawsuit, so until there's a judgment against your daughter, she is not liable to pay anything. If the facts are as you represent, the plaintiff may not win (I would have to know a lot more to assess that possibility). I'm also not seeing from what you say, how the rest of your family might be liable. If the plaintiff will not settle, there will be a trial, and if the plaintiff gets a verdict for more than the insurance coverage, your daughter can explore her options, which could include declaring bankruptcy to discharge the judgement-she should only do this after consulting with an experienced bankrupcy attorney to see if this makes sense. The first step though should be to ask these questions of the attorney retained by your insurance company. I would also recommend that you purchase higher bodily injury coverage limits, which are not very expensive and might prevent this from happening in the future.
Did you have an expert check the braking system and determine what was wrong with it. Where and when was this new old car purchased? Is the school bus company being sued? Was your daughter also injured? There are a lot of questions that need to be addressed by an experienced personal injury attorney.
Was your daughter injured; I gather not from the failure to state that she was hurt. That is the first good news. Your insurer will have to fend her, and you if sued, and the pedestrian may enjoy underinsured coverage on her own auto which would be a source of recovery for her. Tempedestrian's lawyer is likely to be practical and even if it drags on for a while accept the insurance money for a release of liability. And there is the potential of suing the car dealer.