The way it's worded sounds like someone with alts could breed and hatch an alt Sweetling, then potentially trade it to someone without alts and it would stay an alt since it's no longer tied to a specific scroll. Is this really possible now?
It's not possible, no. Someone who has an alt-scroll can breed and hatch an alt on their scroll and so long as it stays on their scroll it will remain an alt. But if the alt-scroll receives an egg from someone else, it will not auto-alt anymore. Hopefully that makes sense?