Read Chapter 232C of the Iowa Code https://www.legis.iowa.gov/docs/code/232c.pdf

Yes. What you’ve described is legal. People under 18 can be arrested and charged with crimes even if they didn’t commit those crimes.

If you or your daughter test positive for meth, she will be removed from your care.

Yes. If you take the car without her permission, she can report the vehicle as stolen and you'll likely be arrested.

If you cannot afford an attorney, you can apply for a court appointed attorney. Go to the courthouse and ask for an application.

You'll need to follow the provisions set out in Chapter 600A of the Iowa Code. Hiring an attorney would be wise.

Sure. 50/50 custody is possible in this situation.

You would need to petition the court to terminate his parental rights. He can’t make this decision without your consent.

She’ll need to file a case in small claims if he doesn’t voluntarily let her get her stuff.

This is a good question for DHS and the child’s other parent.