Summoning mobs with the generic.follow_range attribute doesn't work. I've tried this on wolves, zombies, and husks, but haven't had any success. With wolves, it appears they only aggro towards sheep at 16 blocks which I believe is the default value. I used trapdoors so the wolves can path find to the sheep without them moving any further. As for hostile mobs, it seems it only works on their default value and not the generic.follow_range value. The summon command I'm using is: 

/summon wolf ~ ~ ~ {Attributes:[{Name:"generic.follow_range",Base:33}]}