Also I would say Atilla is usually called Atilla the Hun

Good point, and I think I whiffed a bit on that one. "Atilla" is actually a name still used sometimes today across Europe, so "the Hun" definitely adds some helpful context.

Also since Caesar became a position/title we still say Julius to specifically refer to him.

You mean, in Italy?

In the States, I feel like it's pretty clear that "Caesar" without further context refers to either a leader / dictator / emperor of the Julio-Claudian line, or more commonly to Julius himself. The point being that if you're referring to one of the emperors, it's usually necessary to name them, i.e. "Caesar Tiberius," etc.