After long discussions on Discord, it was generally agreed a few months ago that vanilla text (particularly 'Short History of Morrowind' and dialogue on "Morrowind's economy" and "law in Morrowind") indicates the mainland is governed under native Great House/Temple law, with Vvardenfell being a more Imperialized exception to the norm, and thus that Great House/Temple guards should have dialogue adjustments to reflect this. Here is a long-overdue plugin to implement this.

• Redoran, Dres, Indoril, and Telvanni Guards on the mainland have new Greeting 7s to override their existing Greetings of "I enforce X custom and Imperial law." They use a new topic House law, the response to which looks basically the same as Imperial law, but with a bit more faction-specific flavor to justify the differentiation (fines and compensations are determined by local nobles or priests, not by Imperial magistrates).
• Temple Guards -- that is, Ordinators -- have no new Greetings because "Go about your business. But I'm watching you." already works. But they still have a response to House law.
• Since all Guards have responses for Imperial law, unfiltered by nolore, the above-mentioned guards all have a new overriding response that makes clear why they're exceptions while keeping it simple.
• Savants have responses for House law to mirror vanilla responses to Imperial law.
• Hlaalu Guards are untouched here because per Hlaalu generic dialogue, "We welcome Imperial law and the legions, and the trade they bring." Per 'Grasping Fortune', "We are the only Great House who has embraced the irresistible tides of Imperial law and custom." I think it'd make sense for the Hlaalu to be the exception to the exception, though I'm not dead-set on it or anything.