Unfortunately this will likely take some time. There are some options with equipment, but training is the best long term solution. However if immediate control is what you need, I would recommend the Sporn head halter. Unlike others, it does not turn the dog's head, but brings the dog's nose down. My neighbour has one for their Golden Doodle, and it instantly turned that dog from a bad puller into something her young kids could control.
The excitement at sight of other dogs will take time. Try to redirect his attention to something else, go in a different direction, and keep any contact to a long distance until you start to see some results. Without knowing why he reacts like this it's hard to give advice. I had a boy who had similar issues with some other dogs, but only with close approaches, and mostly I just tried to avoid the situation, but if I couldn't I would ask for a sit, and wait for the other dog to pass.
Edited to ad, personally I think a wide martingale collar is the safest and best tool for walking a Basenji, based on personal experience. They cannot back out of it and because it does tighten when they pull, there is some incentive not to do so. However, you cannot beat training for stopping pulling, and the best approach I know is to not proceed forward when the leash is tight. It can take a lot of patience to achieve the desired result, but most dogs will eventually figure it out if you are consistent. Another approach is to teach them to target (either a target or your hand), with lots of repetition so you can bring them to heel without yanking them around.