So many possibilities... in your area the first possibility that would come to mind is a Passiflora, at least for the arch. You have a lot of semitropical plants to choose from - I am trying to remember from when I lived in New Orleans! Aristolochia has several species such as A, grandiflora and A. gigantea that would be truly spectacular but A. littoralis would be too small.

hyacinth bean vine maybe? I'm growing some of those for the first time this year

I'm in Saraland!

I covered a bunch of old iron work on my front porch with coral honeysuckle (not Jap.) and Carolina jessamine. It's native, evergreen and the hummers love it.

How about moonflower? It has large leaves and big white flowers, very pretty. I covered the old dish with that vine and you can't see that eyesore anymore. I bought the seeds online last year and just planted them in May!

I am not sure of the botanical name, but I saw a vine called tropical bleeding heart. It has dark green foliage, white and red hearts.

The mandevilla has been stunning this year in zone 7 so it should do well in zone 8 for you. Big foliage and big flowers.