Icelandair subsidiary buys Cabo Verde Airlines
 

It's one of the 5 or 6 African airlines that fly to the US i think...

African airspaces are quite "closed". Perhaps they are buying this airline just to obtain licenses to operate in certain countries/routes?
Not unlike when Fastjet (Easyjet) purchased Fly540 in Kenya. That didn't work out the way they had planned it to go, but that is another story. Intra-Africa air travel is extremely expensive, perhaps with the exception of domestic flights in South Africa. There is definitely room for low cost carriers to capitalize on this.

This looks to me to be the South Atlantic version of Icelandair/WOW's current North Atlantic Strategy. Makes total sense.

This is exactly the case: replicate Keflavik. There was an interview with an Icelandair executive today who said they plan to turn Sal Island into a hub with five 757s/767s operating by the summer. The initial business plan is to connect West Africa and the US (avoiding Europe as a connecting point for many) and Southwestern Europe with northern Brazil (avoiding Rio or Sao Paulo for many.) Good luck to them.

The Cape Verde Islands have apparently historically received significant development assistance from Iceland in order to modernize its fisheries industry, so there is a lot of good will there towards to Iceland.