Since you mention expanding I thought of something I heard from a friend who is running an NGO in Uganda. They built a school and other things, and they also sponsor some students. But despite being a strong organization with multiple local people working there, they limit the number of students they sponsor because all the students they sponsor have to be tracked and monitored to make sure the kids are really going to school or actually still need the help, etc. As soon as you get to a dozen kids or more that can become a full time job. You'll need to find someone you can trust to do that, and you'll need to pay them. From a distance that is very hard.

You probably also don't want to focus on just one location to avoid becoming a dominant factor there making people expect that you'll help them. I can actually ask my friend how he approaches that, and if he has some advice. Personally I'd pick only a few cases per village, and more importantly, per school. Because I just remembered another thing my friend experienced: Many of the sponsored kids went to their school, and those kids started sticking together because they thought they were something special. Once he realized that he broke that up of course (I don't know how though) and made sure that the the sponsored kids would integrate with the rest as normal.

You are probably have thought of some of this yourself in some way, but I believe it is helpful to hear it from someone else too, to confirm or challenge your own ideas about that, and learn from the experience of others.