Hi Gill,
I will try to answer your questions. I have been growing them for about 7 years now with success. One thing to keep in mind is I'm in zone 6 and have clay soil and grow them outside.
1. I have never grown them in pots. They are hardy here and stay in the ground year round.
2. I plant my bulbs about 6 inches deep.
3. I have never put compost on them or fertilized them. They grow like weeds here.
4. They like well drained soil and will rot if the soil stays wet a lot.
5. I have grown them in full sun and they will bloom but they don't get very big. I now have them growing on the east side of my house and they are in full sun until about 12 pm and in shade the rest of the day. They are very happy here.
6. Mine usually break ground around the first of March when it's still fairly cool and are just now starting to bloom. I have about 18 plants this year and 9 are blooming.
7. Mine were about 4 feet tall last year but expect them to get taller as the bulb gets bigger.
I hope this info helps.
Jim

They are pretty hardy, I think. I grow mine outdoors just like any other garden plant. It flowers every year.