The reporting on this issue has been strange. I don't know the finer legal points, though I see the logic in each side's claims. It really comes down to legal details on the transaction that few of us here are qualified to speak on. (I happen to fall into the category that thinks that the seller is trying to break the contract because they realize they WAY underpriced their product, but I cannot be certain that they don't have a legal point in their favor.)
The fine legal details likely matter less than some broad legal principles.
Apple is arguing fraud or mistake. The emails that have recently come to light support that. Broadly, nobody should benefit or get hurt by fraud or a mistake.
The problem that Apple has, in my view, is that the trademark registry showed that the the registered owner of the trademark was never a party to the actual sales contract. Broadly, registered owners are not liable for third parties selling their stuff. That is one hugely important reason why public registries exist.
The fact that the seller and the registered owner are affiliates under common ownership is the only "fine point" that I see here. It may come down to whether or not the three Proview entities have identical ownership, or whether "that one guy" merely had an interest in each of the three. At any rate, they seem to be controlled by creditor's committees in the Bankruptcy courts at this point in time, which may also throw more "fine points" into the mix.
But it can be seen, at its heart, as a battle between the two broad principles outlined above.