What a fascinatin’ site! Just clicking around their menu, I agree you’ve picked the test that has the most nutrition-related results. (But I am no kind of health professional!)
For a general health baseline I would go for either the Men’s 75 test package or the Women’s 75 test package, whichever is applicable, for some important numbers the “Health Essentials” lacks, but those don’t have B3 and Omega counts. But any of them would give a good baseline to judge a diet change.