Queen Ariella is clearly the first Queen of Planet Arus based on this series. It is interesting to note that it is established in the original series that the first King of Arus had two sons, one of whom was banished to the neighboring planet which became Pollux and explains how Romelle and Bandor and Allura are blood cousins. The amount of generations between this first king and Ariella is unknown (i.e. there may have been several generations of female rulers before a King came into power).
Though the history in the original series establishes Voltron initially as a single unit robot that was broken into pieces by Haggar. However it is interesting to note Ariella describes five the lion spirits that protected her as a child (that later together somehow must combine to basically form the soul of Voltron even when it was a single entity, then be able to operate independently again as the lions).