I don't think that grabbing her muzzle is abusive, I am just concerned that it is ineffectual, and often will make an irritated, or frightened dog more upset, and make the problem worse. A muzzle grab as a correction (or consequence, or punishment, whatever you want to call it, it's all the same thing) is an established means of telling the dog "I don't like that behavior, stop it"…which is fine in some circumstances. But with some dogs, it merely makes them more angry/defensive; and it certainly isn't appropriate or safe for a child to be performing with the dog (I know you said you are the one doing the correction, not your daughter just thought I would put that out there for others reading.)
Many of us here avoid physical corrections, because in our experience, it has made behavior problems worse, not better. Basenjis are "different", as we all know...and what works for a lot of dogs as far as corrections, may not work for Basenjis.
Don't worry about making mistakes..we all have in the past, and will in the future Dog training has changed TREMENDOUSLY (I can't emphasize that enough) over the past 15 years. Techniques that used to be 'the only way' are now unacceptable to most dog trainers. We all learn as we go
Keep asking questions, and sharing your experiences, and we will help you however we can Think of it as free behavioral advice, from all different points of view