Fantastic article. Exactly what I come to this site for! A detailed all-round look at making a film with few resources.
You probably know this, but… Please be very careful. I know a number of people who work in Africa (NGO workers and journalists) and the poor slums are no joke. Violence, theft and rape are common, and a couple I know who lived in Kenya were almost kidnapped. On a number of occasions.
Make sure you take no risks and have street-savvy local "minders" to help you (not idealistic First-World youngsters who've been there for a month or two) and who can read the on-the-ground situation. You will obviously stick out like a sore thumb there.