Welcome to the forum. It's good to read the posts from breeders that appear here, because all your suggestions and information is welcome to all of us non-breeders.
Aggression is an all encompassing term. As pointed out above, there is quite a range! It is not unusual for Basenjis to be dog aggressive. Mine is, and I just avoid other dogs because I know his intentions are not good. Some are same sex aggressive and fine with members of the opposite sex, and some may just be making a statement when they are leashed. If you describe what you are seeing more specifically I am sure lots of people will have common experiences and possible training fixes to share.
I would love to see some pictures of Tucker, and welcome to the forum!
Welcome and so sorry to hear about the health issues of your two B's…. Thank you for opening up your home to them... And Thank Goodness we now have DNA tests for Fanconi so that no Basenji ever has to suffer with this horrible affliction.
Welcome to the forum Ty and Luna.
There is nothing i can add that hasn't already been said but you have certaily come to the right place for help, information and friendship.
It would be lovely to see a pic of Luna and your two cats.
Hope you get Luna sorted out quickly.