Yes I was going to suggest waiting on the registered name until you know the litter theme (if there is one). My first dog was from an "M" litter and my current dog is from an "SS" litter. I got to choose the first dog's reg name but the breeder had a list of names he liked for Elliot and we debated back and forward until we had one we both liked. From my experience, most breeders don't care what you choose for the call name though.
Congo/Kongo seem like popular basenji names. I like Braz! It's unique and fun.. just like a basenji!