... Keep in mind that once a fee is processed in Bitcoin, it is irreversible. If there is a chain split on the domain records due to a formatting/authentication dispute ... those Bitcoin transactions may be going to an authenticator who in fact never did get the registration done because the majority of the network has ignored that domain registration block
That doesn't really reflect how it works. If there is a chain split, eventually the network will settle on one of the chains. The generator that mined the block in the "winning" chain gets the transaction fee.
There is no "irreversible" payment to the generator in the "losing" chain. Well, in a sense it is irreversible but as they can only spend it in the losing chain it's not much use to them.
I think you got the context mixed up here. The reason why the payment is irreversible is because it is derived from a completely different chain. If there is a chain split in the domain registry chain, the fees spent as bitcoins (going into a completely different system) will have already been spent for those block in the "losing" chain. Transaction going into that "losing block" are essentially a wasted effort.
I'm suggesting that somebody simply sets up enough of the protocol to be able to appear to be following the domain processing rules so as to appear "legit", but they only have to make an appearance to get a block accepted. Perhaps they even get some blocks accepted, but then start to make up stuff or somebody attempts to register an existing name (as a scammer claiming they can hijack a domain from somebody else or however). If there is any reason why the rest of the network doesn't accept the block, for any reason, all of the fees collected by that "miner" or "registrar" would still be collected by that scammer regardless of if it actually gets into the chain.
On the other hand, if the block being "authenticated" is a part of the same chain that creates the currency, this isn't a problem. If the blocks get rejected by the network, any fees (set up in a system like how transaction fees are done with Bitcoin) are also similarly rejected by the network too. Any chain splits remove any fees paid to "losing" blocks and therefore can be ignored. This is why the authentication must happen in the same chain as the transaction. Either that is in Bitcoin or a parallel currency, but if it is with Bitcoin, the authentication must happen within the Bitcoin network too. Otherwise, there isn't a way to get payment to the miner with an outside currency that is similar to Bitcoin without fraud and a significant attack on the payment system. This is fraud because a service is being claimed and paid for, but the service isn't being rendered.
Hacking the data into Bitcoin transactions does not perform authentication of the data and pushes that need somewhere else. In effect, it permits "double spending" of a domain name or allocation of a domain name to more than one person with ambiguity over who actually owns that domain.