You are not legally responsible for anything he purchases after the date of separation.
While is would be helpful to have more facts, based on what you say, you alone are responsible for the home you live in now as you are on the mortgage. In addition, he may have a community property interest in that house since it was acquired during the marriage (regardless of whether or not he is on the deed).
If you are saying that they told their insurance company they they were driving (because they might not have had coverage if you were driving) in order to get the claim paid, they are committing insurance fraud. That is a serious offense.
A person has to come before the court with "clean hands".
I suggest you contact an attorney.
You did not provide enough facts here to properly answer this question. Were you convicted of a crime, or did the child protective services folks just investigate? If they only investigated, there is no case / arrest/ disposition/ criminal record to go to the DOJ. If on the other hand your were arrested and/or convicted then there will be a record at the DOJ.
If you are concerned about what is in your file (assuming you have one) you may contact the DOJ and request a record review.
Depends on the circumstances. Theft, theft by taking, burglary, embezzelment, fraud, check fraud. Take your pick. It's a fact specific analysis.
Before I would sign anything or make an statements I would hire an attorney. Anything you say or sign is going to be used against you. Admissions of guilt are usually never helpful to your case.
I am not licensed to practice in WA, nor do I seek to establish an attorney-client relationship. The following is just informational and based on general legal concepts.
While it would be helpful to have more facts, especially about the nature of the lights and how they are shining on your property, what you are describing would probably fall under the law of nuisance. Under Washington law:
RCW 7.48.010 - Actionable nuisance defined.
The obstruction of any highway or the closing...
It would be helpful to have more facts here. Is the probelm that you co-signed to help her get student loans for college, she hasn't paid them back, they are looking to you, and you want to sue your daughter?