I agree with the others that although he seems to have Basenji in him - his head is def. not Basenji.
As for the leg I'd have it amputated if it troubles him - He'll cope with 3 legs I'm sure, but certainly consult a specialist first. Please keep us updated.
What a pretty girl! Her head/ears/face & wrinkles are Basenji-looking while her coloring & build suggest some Malanois blood–that would account for her size & aloofness, too. Our local SPCA does genetic testing as a fund-raising thing, if you're really curious you could try something like that...
Put a bell on his collar. :)
Ours will start a 500, or bring us a ball to throw… or they start wrestling with each other. During nice weather, we take them outside. Helps A LOT.