What do we call those words which are adjectives used as objective complements and nouns/pronouns used as objective complements
See the terms that describe adjectives or nouns/pronouns used as subjective complements is used appropriately, but I’ve never come across the corresponding terms for objective complements, despite the obvious parallel that they have with their subjective counterparts.
Predicate nominative is an old-fashioned term, derived from Latin grammar, where it contrasted with the predicate accusative employed with causatives. It’s really out of place in English-as-we-have-now-come-to-understand-it, since English adjectives have no case; English nouns have only ‘base’ and ‘possessive’ cases; and even those English pronouns which distinguish ‘subject’ and ‘object’ cases do not employ these in the same way as the Romans employed the nominative and accusative cases in predicate complements.
Terminology is varied, but I think you will be understood if you call those predicate complements which describe or identify the subject subject PCs and those which describe or identify an object object PCs. If you hunger for more adjectival forms, try subject- and object-oriented; the -ive affix, to my mind, just confuses the issue and the reader.