Kids solving Crimes again ahoy.
[X] Don't talk to Hagrid about your concerns.
[X] Share the details of your vision, as you've shared with Neville himself. Ask her to keep an eye out on Neville.
My reasoning is mostly that, well, you would expect Hermione to be disagreeable to this, because, you know, the way she views Divination in canon. But i am pretty sure she gets soured on the idea of it being legitimate, if not always reliable, subject by the disaster trainwreck that is Trelawney. She appears to respect Zagreus's academic prowess. So i think it would be okay to go for the most overt option, because she is not yet disillusioned, and she might have a rivalry going on but clearly respects him as a peer.