There are 2 types of Wargs that can become attachments in Race Across Harad. (Mordor Warg and Racing Warg). Both say, "When Revealed: Attach to an Orc enemy. Limit 1 per enemy. [...]"

Is it 1 Warg attachment in general per enemy? Or 1 Warg of that name? Meaning if Racing Warg is already on the only Orc, I understand another Racing Warg can't attach. But can a Mordor Warg attach to him?

I know 1 Warg makes sense thematically, but heroes can have 2 mounts, so not sure logic helps here.

"Limit 1 per enemy" only applies to copies of the same card, so unless there are other instructions there can be 2 different wargs attached to the orc. Perhaps he switches mounts when the first gets tired.