Most of the non-profit NGOs that I know in Madagascar are actually chartered in other countries. Non-profit status in Mada would give your donors who pay taxes here some tax benefits. But you are much more likely to do fundraising in a wealthier country, where the tax benefit would make a difference to donors. If you just want to do good, you don't have to be a non-profit here, just a company.
But I'd recommend coming as a volunteer for one of the many non-profits here that are already established and dependable. It's a way to find your footing, learn some things, see where the needs are and so on. Peace Corp, for US citizens, is a great way to get language training and be out in the field quickly. There are many other options.