I feel like blackmail is the canon Bonnie route too, I'm being nice to her but she still acts all scared around me other than in a couple of scenes.
I've opted out of blackmailing her simply because I'm not into that. There's more content in the blackmail path, but the main difference reside in the fact that, if you blackmail her, she reacts more angrily towards your presence, whereas if you don't, she's more paranoid than scared, and sometimes she's even flustered when she sees you.
Btw, speaking of Bonnie, there's a wrong render in the titjob scene at her house, right? No matter which outfit you pick (school uniform or bunny), there's a moment in-between where she raises her usual purple shirt and shows you her breasts, however in the scene something different is happening (also with a different outfit, of course). That same render also appears on a school scene with her, while you're both alone inside the classroom.