You said
These new towns will be surrounded by fields of crops and everybody who lives in these towns will have to work together to tend to them. Go back to my original post and see point number
i.e that people in your towns would work farmland around these towns. Where are you going to find all this suitable farmland? Most land suitable for agriculture is already being farmed.
Why are you finding it so difficult to grasp what the idea is? these towns are primarily going to be located in the worst areas, areas where crops can be grown but where they currently aren't and where people are starving.
You said what if people want live on their own farms. If they already have their own farms somewhere then good for them, let them stay there if they want, but those people and villages where they don't are the ones who will benefit from the towns.
Once the worst areas are seen to which will probably take some time other areas could benefit from the towns but not necessarily the farmlands. If the farmland already exists then that doesn't mean local people can't benefit from a better town and standard of living. The idea for the farms on the outskirts is for the areas where there is no farmland. Rwanda clearly has plenty, they won't be the first to gain these towns but when they do the farmland part of it is not required. These towns in areas such as Rwanda will be built bit by bit on existing town and village areas.
this kind of project will take years to accomplish, but then nothing is a quickfix.
EDIT: Who the heck would want to
live like this? better to demolish the place and build a new town over it.
These prefab houses would suffice for the towns homes too, or even these ones
here or something similar. They don't have to be super duper houses like I said before.
These could come in handy as hospitals/medical centres. They're cheap affordable and cheerful but better quality and nicer to live in than what you get in shanty towns. I'm not saying use these actual particular ones, but this is basically the idea of what will be used, perhaps a little bit stronger for longer life.