As African ATC goes, Dakar is actually pretty decent.
Regardless, you would expect both aircraft to have a functioning TCAS.
Off topic perhaps but CEIBA is notorious for not sticking to their published itinerary. I have heard of the Bata-to-Malabo flight being re-routed in mid-air to Mongomo at the call of some VIP's who then kept the plane waiting on the tarmac for hours before taking the trouble to actually show up...