In advanced English morphosyntax and categorical identification, lexical items frequently exhibit functional shift, multi-category distribution, and complex syntactic behavior. Consider the following four advanced propositions regarding nouns, pronouns, adjectives, and adverbs: I. In the complex sentence, 'What baffled the linguist most was how remarkably thoroughly the exceptionally diligent researcher analyzed the anomalous data', the italicized lexemes function respectively as an interrogative pronoun ('What'), a degree adverb modifying another adverb ('remarkably'), a qualitative adjective modifying a noun ('diligent'), and a degree adverb modifying an adjective ('exceptionally'). II. The lexeme 'weekly' in the phrase 'a weekly journal' operates as a descriptive adjective, whereas in the clause 'The journal is published weekly', it functions strictly as a flat adverb of frequency modifying the verb 'published', demonstrating that certain denominal adjectives can also serve as adverbs without suffixation. III. Indefinite pronouns such as 'everyone', 'somebody', and 'anything' require singular verb agreement and can be modified directly by following postpositive adjectives (e.g., 'There is something profound in her analysis'), whereas possessive pronouns like 'yours', 'theirs', and 'ours' function independently as nominal heads without requiring an overt following noun. IV. In the comparative construction 'The more rigorously the scholar investigated the historical archives, the more profoundly comprehensive the theoretical paradigm became', the paired words 'more' function interchangeably as indefinite pronouns governing nominal complements rather than functioning as degree adverbs modifying comparative adjectives and adverbs. Identify the option that correctly evaluates the grammatical, syntactic, and categorical validity of propositions I, II, III, and IV according to standard English grammar and Parts of speech principles.