Well observed, however Hengist & Horsa were Jutes (a non-horse culture) as was the Kingdom of Kent (maybe they were actually a raggle-taggle of several German tribes). The United Saxons used the White Dragon as their symbol. ( Fighting the Welsh- White Dragon Vs. Red Dragon).
But the link of the White Horses of, Saxony and Spain deserves some study. It seems that the White Horse appears all over the place--Hindu, Persian, Greek mythology, even in non-Horsey cultures like Vietnam and Korea. In Britain there is the Uffington White Horse--at least 3000 years old. Perhaps it goes back to the ancient Indo-European Horse society.
I recall the Jutes of Kent as having spent some time with the Franks (instead of heading east like the Angles) so the Cantwarians were probably a mix of Jutes, Angles, Frisians, and the odd Frank.
The Dragon symbol (originally a Wyvern) predates the arrival of the Germanic tribes into Britain. There's some evidence it was brought over by the Sarmatians. Note how it was the westernmost group that adopted it - probably as a means of legitimising their control of the Old Welsh / British lands with less Germanic immigrants.
Yes, Fredrico Garcia Lorca. We're using the Tanya Roder version of the play as it translates better.Is that the Lorca play or is there a new reality TV show?