Everything below is a short summary for northern-Nigeria readers, framed as "handled via Lagos." For anything not covered here, defer to the Lagos page.
These states and the FCT fall under the Abuja Embassy's consular demarcation (centre and north). It's useful for knowing where you sit — but remember, the demarcation governs services for Spanish nationals. Your student visa is still decided in Lagos.
A short overview so you know what to expect. The Lagos guide has the full detail.