The rule extends far beyond the Christological references offered by Sharp.
The “rule“ cannot extend to Christological references without presuppositional circularities. The normative usages, with varying exceptions to help out, apply to human beings. The idea of “persons” can not automatically be assigned to “God” or ”Lord“ or “Spirits, without letting dubious ontological categories, often unaccepted, prefigure the rule, Even dyed-in-wool Athanasian creedalists will say that the ontology persons are radically different than human persons. They will even deny that Jesus Christ is a human being, if I remember, and he is definitely not a human person.
Do we give divine beings “personal descriptions”?
And if the Rule requires a set of Orthodox Trinitarian presuppositions to go into effect (e.g.God is a “person”, which actually is out in left field, but let‘s allow it) then it is worthless as a tool to convince folks who do not share those presuppositions.