Thanks! This feels right, and Wiktionary does indeed use shi- as a prefix-type pronoun, and shí as a stand-alone pronoun, as far as I can see. Do you have any other sources for this (or mind-blowing Navajo language credentials)? Some day hopefully DL will pay for a great bilingual moderator to help nail this sort of thing down! If you have those credentials, maybe you, if they can talk you out of a day job in these revolutionary COVID times...