Agree with Debra. To add: our Lela has the same issues to a lesser extent. Recently we took her to a holostic therapist who looked at her from a TCM-perspective (Traditional Chinese Medicine), and without knowing the dog or the question, she nailed the issue instantly. TCM works with the elements - Lela is a Water-dog (basic emotion = fear); if Water is out of balance, the element that is supported by Water, Wood, becomes weaker. The Wood emotion is anger. Add both, and you get a 'fear biter'. To a certain extent you can compensate the issue with sensible behaviour (see reply Debra).
@nathanyodavis Well, another life, yes, whether it's normal remains to be seen. Many, even dog lovers/owners, find basenjis strange creatures and the way they move around the house (as in couch, table, bed) difficult to appreciate. As long as you realise you have entered a universe where different laws apply and new possibilities arise around the corner every day, you'll be fine.
One of our sisters is called Bintu (Swahili for daughter - Binti for calling her). The other one's official name is Elinor (Arabic for light of god). To find a short name that was connected to that, we went from Elinor to Eleonora (the European version), and from there to Lela (Spanish abbreviation for Eleonora). And a Lela she is 100%.
It would seem that he may be able to learn after he has worked through his fear and anxiety. He seems to be in survival mode. Would it be possible to see a holistic vet or therapist? He may need certain foods, supplements or remedies to help him work through his issues. From the owners of many Spanish rescue dogs that are over here (Netherlands) I hear it can take up to 2 years for them to calm down.
They can do well in a small house, but need walks AND exploration AND interaction with other dogs. Movement is not enough, you need to let them use their mind. When on leash our 2 sisters can sniff all they want, even if it means we do one mile in an hour. They will be tired afterwards.
Trainability: depends on the individual, the age, the human. On YouTube or dedicated fb-pages you can find basenjis showing perfect obedience, even stunningly choreographed doggy dance routines. Will take time and effort and patience. We found that if we treat them along the lines of how you would interact with a 3 year old child, all goes well (most of the times anyway).