Harry: ESTP
Ron: ISFP
Hermione: ISTJ
Dumbledore: ENFP
Snape: INFP (Seems more like ISTJ unless you've watched Snape's diary, where he has masses of Fi and Ne, so he's just a grumpy INFP)
Voldemort: ESTP
Neville: ISFJ
Hargrid: ISTX