From an animation+physics perspective, there is a lot to be said for two-legged rideable animals.
Still, there will be four-legged mounts. In my concept work, the Pantherians tend to ride large animals like rhinos and stuff. Actually, I want to have kind of a cross between a rhinoceros and a bear for them to ride but all of my concept art to date has been based on classic rhinos.
Ok, a rhino-bear sound pretty awesome.
I just got done watching a ton of voxel game youtube videos and honestly you have the most promising game out there. I am so itching for something to do in mythruna! Im going to go build that airship now.