If you don't carry yourself like a violent meathead, it'll be unlikely anyone would view you that way. My best friend loves guys like you and would probably drool all over my keyboard if she read your description.
that sort of guy she wouldn't have much chance of defending herself.
Giving your pet an exotic name would be a very good idea.
You will not find “Daisy”, “Buddy”, “Cuddles” or “Duke” in our list of exotic dog names, but you should find “Zagar”, “Jamiroquai”, or “Bjork”.
It would be nice if there was some sort of way to communicate "This guy right here? No need to worry." without having to wear some obnoxious/creepy sign. I don't usually equate "big" with physically intimidating.
I should get some really brightly colored chuck taylors. To me, physically intimidating is the way someone carries themself.