Creating from scratch, editing a photograph and enlarging a finished file need different tools. Decide what must remain unchanged and what the final piece will be: a poster, product shot, portrait or illustration.
Creation builds a scene from a description. Editing uses uploaded material, but does not guarantee preservation of every untouched detail.
No. Each file should add relevant information rather than contradict the others about appearance, clothing or light.
It is a version name, not a shared resolution scale. Seedream 5.0 Pro and Lite, for example, offer different settings.