I can't tell you about your specific seeds, but had great luck winter sowing 2 species Echinacea pallida and E. paradoxa (seeds were from Echinaceamaniac). Neither has flowered yet but the leaf structure appears to be true to their species.

My Rocky Top hybrid hasn't self-sown that I've noticed, but two of the Big Sky Echinaceas - Sunrise and Summer Sky - reseed ABUNDANTLY in the gardens. The seedlings from these hybrids are quite variable. In general, I don't care for them - they tend to grow tall and floppy, the flower color fades out, and they look like a crazy hodge podge. I am yanking most of them and will get rid of Summer Sky (too orangey) and will deadhead the Sunrise. Not sure about the newer hybrids, but some of them do look nice.

My favorites remain some of cultivars of E. purpurea, but have no idea if they really come true from seed. I've collected seed from 'White Swan' this year for WSing, and will probably buy Magnus or a couple others.

I'm winter sowing some hybrid Echinacea from seed this year as well. I've been told by folks with a lot more experience than I have that 'White Swan' does come true from seed. I would guess that's fairly accurate since the seeds are available for sale commercially. I'm guessing the others will probably revert and resemble one parent or the other. However, like Trudi says on the Wintersown.org website, there are no such things as "Frankenseedlings" so you might end up with something better than either the seed parent or the pollen parent.

I've done well winter sowing 'White Swan' and 'Bravada' Echinaceas.