I guess they could be some of Taim's Asha'man. There was a long delay where the Shadowspawn did nothing and they figured out later it was because they were gathering the male channelers. I always assumed Demandred/Moridin went to go fetch a few of these guys, thus the delay. It's equally possible they went to fetch Asha'man, but the way in which they channeled was suspicious. They held large amounts of saidin and were gathering a large single destructive weave. Seems like Forsaken channeling more than the modus operandi of the Asha'man.