Well, you asked for suggestions. I propose \"ka\" as third person singular pronom for genderless persons. Deklination is \"kir\". AFAIK those words have no meaning in englisch or any other language. But my knowledge on language is very limited.
Another could be iit, ait, ayt or something similar close to \"it\".
Regardless of your choice (it, he, a made up word) i suggest campaigning for it with stories in the roleplay forum. Beside the ingame use.