It’s not whether I consider them Arian. It’s the fact that they don’t hold to Arian theology and don’t consider themselves Arian. Unitarian Universalists are not Arian at all, not even close. Neither are Christadelphians, Biblical Unitarians, or others aqwsed listed.
Perhaps the closest you mentioned is the Mormons. I don’t know if they describe themselves as Arian though. Obviously JWs also reject the label Arian but they do agree with Arius on some crucial features including Jesus’ being God’s first creation. This will apply to some of the tiny Russellite groups too I imagine.
But what I was interested in is the non JW authors aqwsed alluded to who argue for an Arian position. The only one I know is Danny Andre Dixon. I’d be interested to find out about others.