Are there any accelerators in Nigeria/Africa?

There is a difference between an incubator and an accelerator, and the more I look, the more i see that we majorly have incubators in Africa. While some do both, it seems more skewed towards incubation, which is probably what the ecosystem needs ATM.

Dropifi left from MEST and it seems Savanah fund is shipping candidates to 500startups. What exactly does this mean for the ecosystem?

Well, from what I can tell, iDEA Hub at Yaba is an accelerator or at least they are priming themselves to be one.

Yes, there are accelerators and some seems to combine the roles of incubators and accelerators. Find a list here.