If your wife doesn't catch her in the act...its useless to point her towards it and say no. You have to catch her in the act, tell her no, pick her up, and take her outside immediately to finish. Once they've done their business, they don't understand when 5 minutes later you find it and point to a random area and tell them "no." This is why we're telling you that she needs to either be harnessed to your wife, or contained in an area with your wife. That way your wife can always have an eye on her. Without this, you're greatly extending the time that will be needed to potty train as every mistake she makes is a gratification for her that it's alright to do it in the house.
Totally agree. When I am housetraining a dog, when an accident occurs, what happens is...the dog begins to eliminate in the house (this can be anything from sniffing around in a preliminary way to actually beginning to pee or poop). I have leash on that dog, so I immediately tell them once
firmly "quit it!" (or whatever "no" command you use), and take them outside, and they might still be going, but we're still heading towards the door. As soon as we get outside, whether they've laid a pee trail along the path or whether they stopped and take a few minutes to start peeing again, I praise them as soon as they eliminate outside, even if it is like 2 drops.
If the act is already done, even if only seconds have passed, the dog doesn't associate the correction with the act. The rule of thumb in training is 3 seconds (as in, the animal does something wrong, you have 3 seconds to correct it), and honestly I think that is generous. I will correct my animals, but IMO it has to be simultaneous with the unwanted behavior for it to be reliably effective. Correcting the animal after the fact does nothing, and simply scolding the animal without teaching them what to do also does nothing.
Incidentally, I suspect that the last bit (scolding the pup but not teaching her what she should do) is probably the root of your problems. If your wife takes a more active role in training and housebreaking the pup, I would bet these problems disappear.