Yep, read Zande's Put-Off first. I don't worry about your cat being scared of the new dog, but more the new dog harassing the cat. Our basenji doesn't give the cat a chance to breathe (and the basenji has the scars on the muzzle to prove it). I'll be sitting quietly reading somewhere and then I'll hear a loud squeal - 'yep, the cat got the dog again!!' But, I would be more worried about the ducks and macaw. Our girl is obsessed with birds. Someone once told me that basenji's hunted birds as well as vermin, and I can sure see it in our girl, ducks in particular - she'll do anything to get them, as prey! If you find a basenji anything like our dog it'll be obsessed with the macaw and spend 23 hours of the day planning how to get it and the 24th hour attempting to get it. As Dagadingo says you'll have to evaluate the character. Good luck and best wishes with your decision and thank you for taking the time to seek advice and get the info before hand.
P.S. Here is our girl stalking a possum in the tree (most of her morning gone just doing this). And even though our breeder said that our girl was a climber she's never been over this small fence once, yet!!