Apolaki:
The close up picture of the mounted figure really looks like Benin work to me. The Kingdom of Dahomey was, of course, located in what is now Benin, and this piece might date from that period although I think it is later. There are some nice examples of Dahomey/Benin art in the Pitt-Rivers Museum in Oxford, and you can see some of it here
http://www.gutenberg.org/files/44014...-h/44014-h.htm
There are a number of swords/knives shown on that site, some of which resemble the shape of your blade, some have piercings to the blade with incised marks, and a couple have figural hilts, but none show all of the features on your example.
Nice sword and I hope you can find the answers to your questions.
Regards,
Ian.