You might post this on the Allium thread and get more answers. I have no idea and I wouldn't want to point you in the wrong direction.

If they did well after your first try at dividing I would just repeat that! Replant at the same depth, I think the necks should stay underground, you might want to wait till the muddiness dries up a bit though. Spring should be a good time. They bloom in late summer, right? Dividing in the spring should give them plenty if time to settle in again, but alliums are pretty tough so don't worry too much!

They're pretty much evergreen here given the moisture.

Katob is correct. You can divide now...you can wait, whatever you want.

Yes, they bloom in late summer. Most of the foliage dies back here, but I was left with a few grassy leaves that survived the winter. When I first planted them they were in a pot...this made it easier to tell where the soil line was. I actually did divide them, but when I ripped the bulbs apart I found a long white neck, and wasn't sure if it should go above ground or below. I ended up replanting some with a little of the neck sticking out. Wondering if I should dig them up and replant them deeper, or pile dirt on top in a little hill.