Basenji myths... hmm. So don't know if it's true or not but I recall hearing, if not reading (although I can't find a corroborating online source) that the leading cause of death for Basenjis is getting hit by a car. We were warned NOT to turn our first Basenji loose anywhere near traffic, and we never did. I still won't.
I agree with @DonC recall, recall, recall, and when you've got that down... more recall. It's been my experience that Basenjis can lose their head when they're either on a sent or see something they really really want. For mine it's squirrels. They see a squirrel... stern command, clicker, praise, treat... NOTHING MATTERS. Maybe a bit of hyperbole. Still, there could be a big ol' LOUD freight train baring down between them and the squirrel... wouldn't matter. They'd never see or hear it. Like I said, they'd lose their head IF I weren't there to intercede.
I'm not saying don't turn him loose. Instead, I hope I'm encouraging you to be really careful. All that said... He's SO cute! And I think he's found a great home. 6 weeks is early, but it sounds like you've risen to the challenge! Love the training so far too.