Who is your target market? For an adult to take nearly a year out of their life is a big ask. For whom do you expect it will be worth it? Staff/campaigners at existing non-profits? Existing bloggers/youtubers etc on related subjects? Anyone else? How large is the potential pool of students and how will you reach them and convince them that the course is worth the time and money?
I realise this is not a commercial project, but I think you would benefit from some start-up like thinking: who is this product for, what is the market, how do you reach customers, what is a minimum viable product from which to iterate? Apologies if you have already done that, but it wasn’t communicated in your post.
Ok, sorry for the misplaced advice. Good luck with the school!