Best suggestion I can give you is not steal someone's art in the future, there are many alternatives to this that it's a bit inexcusable
I wasn't aware of that. Either way, my point stands, this person should probably use other methods instead of asking artists to use things they've already used in the past. That would avoid confusion and make their work their own instead of being compared to somebody else.
Commissioning, using assets that are already available for free right here on this site, 3d characters etc... But if people are up for a low res and poorly edited Hermione more power to them.