The height of the Lilies depends greatly on the growing conditions. Even in the same garden Lilies can have different size if planted in different places. All numbers you can find in the Internet are approximate.
All Lilies bloom once a year - for 2-3 weeks, depending on how many buds they have.
Please note that in your zone they might not bloom well: Lilies need a cold period (vernalization) every winter for blooming.

Easter lilies do fine all the way down to Jones Creek and maybe even farther. Jones Creek Texas is about 20 miles from the Gulf Coast and I have seen a lot of them there for quite a few years. They all seemed to stand 3'-4' tall and look great. Many people down this way get them as gifts during the Easter season and they just stick them inot the ground and let them go.