Yep, he'd be recognized as a demon, assuming he's not out of her range or things aren't jamming her sixth sense. Though I forgot to mention that she'd probably send off a telepathic "hi there, can I help you?" message first once she realizes he's there, whether or not he can actually communicate telepathically. She'd be surprised if he couldn't, but hey that can just be another topic in the discrepancies between their worlds. Never mind that it seems to wildly vary who can and who can't telepath in canon

Also I don't want to spam your post anymore, so I'll just post what I was going to answer for Maka here: yes, do all the running with it, she'd be surprised and...kind of upset with herself really because "oh god that sounds so unhygienic"

(And Jade's not entirely unkillable, just for any death besides a noble one)