Hi Anette. Great question!
Our plant database says this:
Propagation: Seeds: Sow in situ or Start indoors
Propagation: Other methods: Bulbs
Ornamental Onion (Allium schubertii)
So presumably you CAN get seeds to germinate.
Maybe some of the 11 ATP members who have the plant would talk about whether they ever tried to germinate seeds and how true to the parents the offspring were.
I don't see "F1" anywhere, or any cultivar names, so presumably it is just the species and ought to come as true to the parents as any plant would that hasn't been inbred for generations.
I found this in "hortipedia":
The plants prefer a sunny situation on dry to moderately moist soil. The substrate should be sandy-loamy, gritty-loamy or sandy clay soil. They tolerate temperatures down to -18°C (USDA zone 7).