OK, it's been found now, but for future ref, let us recall that the ELTs on airliners are only activated by contact with water (hence their correct name: Underwater Locator Beacons). This one may have been activated by the swamp water, if it ever was.
Yes, remarkable similarities to the Abidjan crash, but still probably unrelated. As I recall it, that plane had dinged its AOA vane in collision with a ground vehicle, giving a false stall warning on TO which had the crew fly it into the water (very dark night).
For those who hate speculation, remember that barely any African countries ever publish the full accident investigation reports, including the KQ at Abidjan. Unless there was a total power loss at the beginning of the Douala accident chain, it is the CVR-DFDR read-outs that will probably give the answers. That should take a week or so after the boxes are recovered and delivered to the NTSB.