You can also try a DAP or Beaphar collar, it contains pheremones which can help with anxiety and stress in dogs (and cats!).

Also the bit about the harness, I wouldn't push it til she bites you obviously, but don't let her keep getting her own way. Either she has a harness on and you go for a walk, or no walk.

Lots of treats and praise when you're putting the harness on, if it's got to the stage where she won't let you near her with the harness because she's associated it with the fireworks then you'll have to desensitise her to the harness. Leave it on the floor and when she goes near it praise and treat so she thinks 'oooh the harness, this means good stuff'.

Does that make sense?

Good luck! The fireworks will all be over in a few weeks with any luck!