I like your approach... if I were concerned with preserving the Nigerian state I would take the same.
As a Libertarian / Anarcho-Capitalist type... my own solution would probably be entirely different. I would look to decentralize and carve up the region by interest groups, clans, ethnicities, etc.
I wouldn't stop with Nigeria of course... I would do this to the entire globe.
I like the meta-approach. You're thinking way bigger heheheh seek first the human commonalities then build up to the differences from there. Not too dissimilar from what I theorized albeit I'm starting from a point of "let's get some actual infrastructure and some institutional memory of things working properly" first before we start to dig into tribal and ethnic worries.