Put the following code in a plugin:
JavaScript:
(function() {
const old_name = Game_Enemy.prototype.originalName;
Game_Enemy.prototype.originalName = function() {
var name = old_name.call(this);
name = Window_Base.prototype.convertEscapeCharacters(name);
name = name.replace(/\x1b([{}<>.|!$\^]|[A-Z]+)/gi, '');
return name;
};
})()
Then you can use some text codes (\V, \N, \P, \G) in the enemy name (only codes that substitute text will work; colour codes or control codes like \$ will not). For your use-case, write \N[4] to set the enemy's name to match that of actor 4.
I haven't tested that code, but I'm using a similar technique for setting a skill name to match an actor's name (for a summon skill), so if it doesn't work it'll just be a minor error that can be easily fixed. Let me know.