Hi! Thank you for your interest ^^ you’re right, it’s better to have clarification!
Yes, those kind of changes are free! Restarting from scratch would be something like changing the shape and/or background, basically the structure of the signature. Changing text or villagers takes very little time, and I understand those change often, so I’m not charging for it, even several times
Another option is to list all your dreamies, so I can include all of them, and when you get them, I can put little pixels next to them to signify they’re obtained. This is also always free. So it’s up to you, whether you want your current villagers, or your dreamies, on the signature!