It's been a few years since I worked in child protective services (yes, I was a baby snatcher). Even in today's extremely PC world with it's absolute zero tolerance for common sense, I do not see the confiscation/committment horror show you are worrying about. At least not if you have even the remnants of hind legs to stand on.
THEY can snatch away your kid for up to 72 hours on an emergency basis with no prior paperwork, but if you offer any resistance THEY are going to need to regroup and get the cops to accompany them, which meansTHEY have the time to file an application for an emergency petition which means THEY are going to have to comply with pretty much all of the due process stuff before even coming into your home. You can stand at the threshhold and say "No entry without paperrwork" and it is valid. What THEY come back with is not a warrant but still a valid order the cops must enforce.
Once the cops assist THEM in snatching up your kid(s) it will be very difficult for the cops to confiscate your firearms, as there are no more kid(s) in the home to be harmed by the firearms. As the whole kid snatching thing is a civil, as opposed to criminal, matter the cops cannot play the "evidence" game. (Of course, if you have Class III stuff laying about they can ask to see the tax stamps, but once that is done the cops have no reason to confiscate or seize anything.) [If you have a few hours, ask me about the difference between confiscate and sieze ]
The real fun will begin after you have your child-snatching hearing in the Juvenile and Domestic Relations District Court - a court not of record. There will be no transcript made by the court. If you want to pay for a court reporter you may. Most courts do not permit audio or video taping of proceedings.
After you kid is returned to you because THEY could not convince the judge thast your kid(s) were in immenent danger of physical or emotional harm, THEY might attempt to proceed with "regular" child abuse/neglect" activities, such as insisting you get counseling or give away your firearms. THEY will do that after informing you in writing that THEY made a determination thast your kid(s) were exposed to something that meets the statutory definition and local interpretation of child abuse/neglect, and that your name and personal identifying data have been placed in the child abuse registry.
Your next step is to appeal THEIR determination, Based on your scenario itshould be easy, but you will benefit from paying a lawyer versed in the intricasies to do m,ost of the speaking and writing for you.
Once that is done, you will want to get another lawyer - this time one well-versed in civil rights violation suits. Again, based on your scenario, you should look at the expense as investing in your kid(s) college education fund and your retirement fund.
Somewhere along the way, you will want to get a personal injury lawyer to sue THEM for the emotional scars THEY caused both the kid(s) and you. This is investing in your vacation-for-life fund.
On the other hand, if MY kid pulled a stunt like that, I might be inclined to let them remain in foster care for the rest of their natural adolescence. I'd just concentrate on getting my property returned and suing THEM for my emotional scars.
Remember, I said I might let my kid get away with that sort of thing. It depends on how good a story they cooked up about me.