Wish I could cheer and encourage your endeavor, but "use of public resources and adherence to public protocol" are poison pills, imho.
As granny used to say, he who pays the piper calls the tune. Government will be calling the tune.
I understand that Indiana homeschooling laws are mild compared to my state (Pennsylvania, which has an atrocious set of standards to homeschool) but a charter school is accountable to the state dept of education.
Better than public school, to be sure. But expect that call from the gov't: "...and I'm here to help."
Indeed, the involvement of government will be a significant challenge. There is a point at which the “tune” they call will be contrary to our mission, at which time they will be met with reasoned and clear practices to the contrary. We are Americans. There are ways to get this done with persistence, patience, ingenuity, hard work, and so forth.
I wish you the best.