Yeah, Botanicare isn't organic but they have an organic-based line (pure blend pro) that doesn't have the OMRI sticker on it but is an EXCELLENT product and I consider herb grown with it equivalent to organic.
If your water source is tap, and you're in soil, you don't need calmag.
Don't use pre-ferted soil on small seedlings. Sunshine Mix from what I have heard is pretty mild though and might work; test it on bagseeds- if they grow to 3 sets of adult leaves without turning yellow, you're in business.