A business plan for a small business overseas investment should get redacted after visiting the place. Before visiting a new place entrepreneurs need to forget everything he/she knows about business generally and for his/her specific business object . Know well there is nothing, but nothing ordinary standard in business around the world.
In some places, especially in poor places, internet information are not enough and are not always right. As soon internet is not developed enough and especially if entrepreneurs don't speak the local language. Relying a business plan on information from the net has a high probability to fail. How smaller a place is, or how poorer so more unofficially side rules exist, most of them is difficult to find anywhere about in the internet.
There are a long list of unacceptable spending somebody need to do. Starting from the very small amount for getting a taxi at night because you find out it's dangerous to walk on the streets that late. The necessity of paying people for services you don't even know they exist, as your corruption mediator, even if it's well known in some places how necessary it is to give some cash to get your job done, usually it's unknown that foreigners can not corrupt right away but need support of a local who finally will also get paid.
Don't try to make something different, or try to teach people how to do what they do, because they do it for long and there whole society is build so, if anyone corrupts, than also corrupt, if anyone avoid a particular place, avoided too, follow the people to know them, don't go against them, knowing them will change a lot your Business Plan.
Redact a business plan after arriving and after understanding the place and the people, but don't go without any plan neither. Make a draft or a preplan and work on it during your stay