I read something on Wiki, about the Ellimist. Having never read the Ellimist Chronicles, I can't say if this is a reliable fact or not. Apparently, the Ellimist, at some point during the Chronicles, merged his consciousness with an Andalite and had a family. According to that wiki page--and another about minor Andalites-- the Ellimist had a few children that he named after various natural elements--Tree, Grass, Sky, etc-- and other Andalite herds used similar names.
So, if we assume that the old-Andalites kept this tradition of using the same names, then we may actually have an explanation for why these Andalites share the name Esgarrouth.
Or, for the reasons above; heroes, etc.