Your graphic from HSLDA is a bit misleading. Washington state is quite hands off. We do have to submit a declaration of intent to homeschool – a one page piece of paper. (But age of compulsory education is 8, so when I took my son out of kindergarten, they didn’t want any paperwork.) If a parent or responsible adult has had at least 45 hours of college credit, that’s that. If not, there’s a class the adult can take to qualify (I think it’s a weekend thing at a community college). There is a requirement for annual testing but you don’t need to submit scores or anything. I think there is the remote possibility of being audited, so maintaining some sort of records is advisable, but there is no requirement for any curriculum or courses or anything like that. Very Unschooling friendly.
Given your review process, seems MD ought to be a darker blue on the map.