How far can you go with Lawyer-Friendly Cameo?

I'm curious how closely a Lawyer-Friendly Cameo could resemble another character before it starts to become plagiarism. Hypothetically, say I introduce a character named Homer, who is a fat drunk and complains that his son is a troublemaker. Could I mention a Mr. Wayne, who's a billionaire and is really passionate about justice? Are these fine legally or would those examples be considered plagiarism?

If anything, those would be considered Shout-Out examples, not plagiarism.