Horde Prime's consciousness is destroyed, freeing his clone brothers; allowing them to forget identities of their own like Hordak and Wrong Hordak.
In the vision of the future Adora has, Glimmer and Bow are married. Bow has one of Glimmer's earrings; its Etheria custom to swap jewelry between partners as a symbol of marriage.
As the space travel Adora, Catra, Bow and Glimmer did on screen didn't involve inhabited planets aside from Etheria, it's unknown how badly Horde Prime's evil reign damaged the universe.
Hordak and Etrapta were confirmed, by ND Stevenson, to have been sent back to beast island as penance. Though they manage to restore order and build a life for themselves.