Ezn called it the "Lavender Unicorn Syndrome". It is far from being a fandom specific problem.
I will refer to it as such, or "LUS" in this, because it is the shortest way that comes to mind, even though this guide is meant to be fandom neutral.
First of all, I want to explain what the problem is.
In an attempt to avoid repetitive writing, writers will try to refer to characters by anything that isn't their name or their pronouns. This itself can become bad writing. Honestly, it reads kind of pretentious at some points.
There are two ways to help against the symptome.
If you want to use substitutes, try to keep them relevant to the scene.
Or: if a character has a name, use it!
While names are, like said, an invisible prose piece, they can be overused. That's why we use pronouns. Ezn recommends to replace as many name mentions with pronouns.
I don't say this is bad advice. But I argue you should mention the name regularly, especially if mutiple characters are mentioned close to each other, to avoid confusion. I have this problem often when I read, so I wanted to just mention it. Use the names.
That this syndrome appears may happen because of repetitive sentence structures. Just restructure the sentences until it is gone.
The descriptors writers use instead of names can fit, if the context allows it. It has to relate to the scene. Does a characters height matter in the scene? Do they talk about hair colors?
These descriptions can work if the view point is limited, if a characters name isn't known yet.