The idea that you have to be the pack leader and assert yourself the right way to correct unwanted behavior is, unfortunately, a myth. The dominance method is not based in science and is the incorrect way to view dog behavior. The reasons that dogs do what they do have much simpler explanations than that they are testing you or trying to pull a fast one on you. This is why I urge you to seek out a trainer who is credentialed. Prong collars can increase aggression and solidify negative associations with other dogs. If you go Googling or YouTubing, make sure you first look at the source of the video or article. Is it from a trainer? If so, what are their credentials? (Google to find out.) What basis do they have for giving their advice?
There is a proper way to train dogs who are leash-aggressive, and the wrong methods (like dominance- or force-based methods) can backfire and lead to more aggression. That is why I would encouraged you to read out to a certified trainer for a consultation. You can location trainers in your area via the following websites:
CCPDT website: http://www.ccpdt.org/dog.../certified-dog-trainer-directory/
KPA CTP: https://www.karenpryoracademy.com/find-a-trainer
The trainer may be able to advise on the behavior at the dog park too, although I agree with the other posters that it would be best to take a break from the dog park until you have things sorted. Best of luck!
If you're on Facebook, there's a private group called Golden Opportunities that is for breeders, rescues, etc. to post retired show dogs or older adults for sale. You have to answer all the questions to get into the group, but it's a great resource. Adults pop up regularly several times a year for sale.
I would suggest a dog of similar age, energy level, and personality to your basenji rather than focusing on a particular breed. Since you're going the adoption route rather than the breeder route, your possibilities are potentially limitless. Read adoption profiles for your local shelter, Petfinder, rescue, etc. carefully. Dogs being fostered in actual homes by people are probably likely to have slightly more accurate information about them, since they're being observed in a home environment rather than a shelter. Best of luck!
Also, I don't know how much research you've done into the breed, but even if you have, it's worth reading this guide from Basenji Rescue and Transport (BRAT) before committing to a basenji. Only you can answer these questions honestly.
"Is a Basenji the right dog for me and my family?
If everyone thinking about getting a Basenji would ask this question, there would probably be fewer Basenjis in rescue. The best way to answer it is to think about yourself, your family, why you want a dog, and what you want from your dog.
Consider the following:
Is your home life pretty hectic right now, with small children and lots of activity? Are you caring for a dependent family member? Do you need to be away many hours each day because of your job or because you travel often?
What kind of dog do you want? Do you want one that is highly obedient and lives only to please you? Do you want one that can safely be allowed to run off-leash? Do you want one that just likes to lie around the house all of the time? Do you want a dog that has never met a stranger and instantly loves everyone, including small children?
“Yes” responses to any of these questions should lead you to question whether a Basenji is right for you. Basenjis are obedient some of the time, but they are sight hounds, bred for generations to be independent thinkers. They need both physical and mental stimulation, and if they see anything of interest to pursue (literally or figuratively), they will not hesitate to pursue it.
Basenjis are active, often fearless dogs that, when off-leash, may run in front of a vehicle without the slightest sense of danger. This behavior is driven by the Basenji's survival instinct and should not be underestimated. Some Basenjis are outgoing, but others are more reserved and need to be allowed to warm up to strangers before being petted. Many are wonderful with children, but others don’t like them much at all. Again, refer to the Reality Stories on this site to find out some of the truths about life with Basenjis.
Do you want an intelligent dog? Do you want a dog that will challenge you and may even outsmart you on occasion? Do you want a dog that is cheerfully disobedient? Are you willing to laugh at yourself when your dog puts one over on you?
If you answered “yes” to these questions, a Basenji might be just the right dog for you.
Are you willing to put in the time and effort it takes to be a Basenji owner? Will you go to training with the attitude that the training is more for you than for your Basenji? Are you willing to take your Basenji for long walks, play silly games, cuddle as needed, and provide the consistent care and nurturing a Basenji needs?
If you answered “yes” to these questions, a Basenji may be waiting for you."
If you need help finding a responsibly bred basenji puppy, I would email the Basenji Club of America (BCOA) breeder liaison Denise Vertrees: email@example.com She can give you names of breeders in your general area who might have puppies or adult dogs. The Basenji Club of America breeder directory is another place I would look for breeders: https://www.basenji.org/index.php (You may have already done this, but just in case ...)
AKC Puppyfinder Marketplace is NOT an ideal place to find a basenji puppy. While a few reputable breeders do advertise there, so do several well-known backyard breeders and even a puppy mill. If you are not familiar with the concept of a puppy mill, please see this information from the ASPCA: https://www.aspca.org/barred-from-love/puppy-mills-101 AKC registration does not mean "well-bred." Learn how to screen a basenji breeder here to make sure you are not supporting a less-than-responsible one: https://www.basenji.org/learn/ScreeningBreeders.htm
Remember that your puppy's sire and dam (parents) should always be tested for Fanconi syndrome and progressive retinal atrophy (PRA) at minimum, and that at least one parent should test Clear / Normal for the disease. The BCOA recommends that the puppy's parents should also have hips, eyes, and thyroid evaluations. You can find proof that the breeder has done health testing through the site ofa.org. A good breeder will be there for you throughout your puppy's entire life to provide support and advice, and to take the puppy back at any point if circumstances arise where you can no longer keep it, helping to ensure that your basenji never ends up in a shelter or on Craigslist.
And don't be intimidated--most breeders who participate in conformation (dog shows) keep only one or two puppies for show; the rest go to pet homes like yours!
If you have any questions about basenjis or the breeder you're communicating with, you should join this Facebook group: https://www.facebook.com/groups/536851013130196/
Best of luck in your search! If you can wait until the end of this year / beginning of next to bring a puppy home, you'll have a much better chance of finding one. Hope this was helpful.