Lily was a little startled by the girl suddenly simply being there, and while she had started to reach for her wand out of reflex, she relaxed when it appeared Remus knew the girl.
She had no objection to the company, so she smiled softly and murmured her own "hello" to Raven, introducing herself after Harry had.
Granted, she'd want any non-wizarding sorts to be extra careful, and she made a note to keep an eye on the girl, just in case.