I don't see anything on your list that requires darkness to germinate. I'd surface sow all, or very lightly cover...placing just a bit of the sowing medium or some grit on top to insure good soil contact.

I've sown somniferum and nudicale plenty of times direct sowing anywhere from earliest winter to earliest spring (Z 8b)- direct sowing: literally tossing the seeds into beds where I would like to see the plants grow. I haven't attempted to cover seeds at all.

The p. rupifragum might benefit from a brief moist chill of 2 weeks or so (40ish F) - does not always need it but you might experience more complete germination with a moist chill.

Thank you. I'm not sure why my list has darkness down for some... Will have to fix that.

Do you have any troubles with birds eating the seeds? Every time I try to direct sow, the seeds go missing in a few days. It makes things a bit complicated when trying to start plants that resent transplanting.