I suspect that she feels that the Bradys have "run" the town for a long time. She wants to be the one who takes them down a peg or two and show that they are not favored. I suspect EJ being Sami’s gu is also a motive cause he is a DiMera.
I think that she is an up and comer who thinks that this case is a stepping stone to get a promotion and notority.
Asfor Bernardi’s wife, how else would you expect her to react? My guess is she is in the dark about her husband’s cnnection to Stefano!