Here’s a sentence like one I used to use in my corporate writing seminars. See if you think the given pronouns are correct:
She and I approve of Martin traveling with them and we.
Did you find any problems? It’s easy to evaluate if you take it one at a time, pronoun by pronoun.
She approves…. So far, so good, right?
I approve…. OK by me. You too?
I approve of Martin traveling with them…. Also fine.
I approve of Martin traveling with we. Ouch.
You can hear that you need us for the final pronoun. (Us is the object of the preposition with. Prepositions are always followed by nouns or object pronouns.) Other than that one change, the rest of the sentence was grammatically correct. So even when a sentence seems overly complicated, if you take it one little piece at a time, you should be able to sort it out and make sure it’s right.