This is what Clothier says
"Echinacea pallida, and purpurea , Sow at 20ºC (68ºF), if no germination in 3-4 wks, move to -4 to +4ºC (24-39ºF) for 2-4 wks
Echinacea angustifolia, paradoxa, and tennesseensis , Sow at 18-22ºC (64-71ºF) for 2-4 wks, move to 4ºC (40ºF) for 9 wks, move to 10ºC (50ºF) for germination "
So, cold strat is probably helpful though not necessarily an absolute need. And some might do best with warm-cold-warm according to him. I'd never do all that rigamarole, I'd just wintersow. The fluctuating temps with WSing does seem to help a lot of seeds overcome dormancy. I find most any really fresh seed, as in just dropped naturally from the plant, will tend to grow immediately. The longer the seeds are stored, the more likely the dormancy issues and the more persnickety they tend to be about germination.
I have wintersown ech purpurea several times with success.
I might add, some of the newer hybrid echs do not produce viable seeds so if you've harvested seeds from those, or obtained them in trade, you might not want to get your hopes up too high. But regular old ech purpurea, or commercial seeds, should work well with wintersowing.
Karen