We don't know for sure about the griffins yet. And the horses really belong to Elrath himself :)
Added 6 minutes later
I wonder how the riders will move. Maybe their horses of light will have wings that appear when they move, or they will move like ordinary riders (the weapon used for the charge attack suggests the latter). If the Sun Riders are champions, then I was right when I called the riders champions. And also, the description says that Elrath chooses the best of the knights. Perhaps there will be swordsmen or riders on ordinary horses (the latter is nonsense, but these are just my thoughts).
Демократия есть одурачивание народа при помощи народа ради блага народа.(Уайльд Оскар)