You are right for the first paragraph apart from making it from your body.
You are right here too. Smoke actually is manipulated by your chakra so, you must already have a smoke to manipulate. so it acts as nomal smoke would. Though because your chakra is present, You are able to shape it.
Yes you can though would a smoke from a ciggerette be enough? it'll be small in my oppinion, a reason why people have not used that idea. Though I may be wrong depending on how you plan on executing it.
In addition,
Smoke is a collection of airborne solid and liquid particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. That is what my firend Wikipedia says, but short and in layman's terms it what you've said.
Smoke is not an actual element, which means that we can't just "blow" the smoke directly out of our mouth, or any other ways. For that we use accessories like a gas mask, some smoke bombs, or a wrist launcher. Wrist launcher seems like the best and the easies way to do it. But, the launcher that you remember Kiho used was too big and messy. That's why I'm warmly suggesting you to state in your bio update that you have a one barrel launcher which enables you to move a lot easier and faster, and it practically serves the same purpose. Plus, without a wrist launcher, you can't perform a specific Smoke technique.
You can always first create a Fire jutsu, and then wait for it to start burning something and the smoke to show up. Is that really the best solution, with it taking more chakra and precious time? Though it could work and you may use it as a tactics. Or say a clash of fire and something that creates a cloud of smoke, would give you an abundant source of smoke to use.
Now, elemental relations... There's no element where if techniques of equal rank clash, the Smoke would win out, simply because is even lighter than air. So, it's can't break through any attack/defense. But unfortunately, Smoke does have elemental weaknesses, and that are Wind and Water. Wind can simply blow away the smoke. Water of the other hand, soaks up the smoke particles consuming it.
Do you understand everything? What accesory do you choose?