Back to basic training. Practice sits and downs (anything else fun to the Basenji) in a controlled environment repeatedly (5 minutes at a time).
Go in a SLIGHTLY less controlled environment (front of the house will do for some dogs) and practice the same with better rewards (2 minutes at a time).
Increase distractions. Eventually work just far enough from a likely instigator for 1 minute max and work towards 3 minutes. Then decrease the distance slowly. This is to show your dog that he can listen, sit, and get a reward (even while glaring at another dog). Work towards being his focus and being more interesting than the other dog. It is best if you have a very cooperative helper (owner of other dogs who knows what you are trying to do).
If you can find a trainer that knows this approach and can help you through it, that would be great.
Good luck and use small frequent training sessions. (...wear thick jeans when walking your dog... it hurts.)
SciDiet beats nothing. Try the Kidney formula. I would recommend canned food for kidney problems.
The mammal meat requirement is from 'wet meat' and NOT dry food (dry food changes the protein). Some wet mammal meat should be part of the diet (I am not up-to-date with the hybrid protocol) so check the meat for kidney diet (usually chicken and pork… so a bit of pork daily could be good).
Home-made diets can be great but make SURE that it is balanced (minerals and vitamins) and you may have to repeat bloodwork after a couple of weeks to ensure that the mineral supplements are in correct amounts (the ones that can be measured in any case). Most homemade food require some supplements. DO NOT ADD the supplements while the food is warm. Wait until it is cold. Omega-3 can help too (fish oil or flax seed oil).
Use rigatoni pasta to hide the pills. Good pocket shape!