You will have to domesticate the judgment in Washington state. An attorney there may take the case on contingency but the judgment is so small, there's not much for them to collect. If the judgment is against a business, our firm may be able to collect without domesticating the judgment.
Parents are rarely held criminally liable for the acts of their children. Civil liability, however, is an entirely different issue. Your question also touches on a violation of the statute of limitations. I recommend that you or the child contact a criminal defense attorney.
The DA has a lot of discretion to charge you with anything that they can. The DA could lose the ability to charge you with crimes if they fail to do so. You should contact an attorney to make sure that you get fair treatment.
Terminating probation early and expunging your record will help you get a job, keep your job, and get other benefits that society might otherwise deprive you of due to having forfeited some of those rights by committing a crime. A court will often grant these requests if you can show that you have served your sentence and are on the right path. Multiple applications will not hurt your case necessarily, but it does cost money each time you apply. You can fill out the forms, and make the...
If this occurred in Australia, then you should consult an attorney there. If it happened here, you should hire an attorney to appear and hopefully get the sentenced reduced. For a first offense, and since it is a low value, you can likely pay a small fine and then get your record expunged.