He's a very strong two-way player so Doughty, Pietrangelo, Yandle and Keith are very good comparisons, but I don't think he has the mean streak/emotional play that Doughty has.
Think... Doughty, but not as many big hits and not yelling at refs haha.
Hanifin is rock solid in his own zone, doesn't make many mistakes and has great offensive instincts.
I've only had 5-10 viewings of Hanifin, and about 10-15 of Ekblad, but if I'm an NHL GM I'd want Hanifin > Ekblad.