Oh, this is most certainly possible! A smoke elemental would likely have a Fire elemental and an Air elemental somewhere in their ancestry, though a Fire and Wood heritage, while rare, is also possible. Fire is basically required for this elemental power to exist.
At level seven, powers would likely involve summoning smoke, dissolving into smoke, and the ability to travel/vanish using smoke bomb like techniques. An additional ability would be the ability to filter pollution out of the air due to the substances some smokes would be made out of, and the ability to breathe in contaminated air. This would prevent the elemental from choking on their own element. They may also have minor control over things like haze, smog, and fog, but likely not much.Background Character Blurb: Dorian Mantel is a fifty year old overdramatic pyrotechnician who works with various famous celebrities and their concerts. He regulates the smoke effects and the fog on stage when things are needed, and he adores dramatic entrances. He has a cigarette addiction that he keeps saying he’s going to break, but never gets around to. Besides cigarettes and drama, he likes pop music, honey, barbeque, and dreams of moving to Australia some day after he retires. He dislikes bitter foods, polyester clothes, and loud noises. He wears earplugs during concerts.