It's difficult to tell what he may be (in terms of breed/mix). A photo of him standing from the side, which shows his profile, would be helpful. Basenji's are square... as tall as they are long -- shoulders to tail, shoulders to toes. The eye's in your pictures are blue... most babies have blue eyes, so watch for the eye color to change as this little one grows up. That said, I am not a breeder and so, I am not as familiar with Basenji pups as a breeder would be.
A DNA test could tell you for sure. Ask whichever Veteranarian you choose what they think.
Congrats on your new little guy... he sure is cute!