For bakeries, depends on what you want...
The 2 most popular one in the North End are Mike's and Modern. They are both on Hanover St.
If you want cannoli, go to Modern...they fill them when ordered, not ahead of time.
If you want pistachio macaroons go to Mike's...
I'm not so versed on the seafood places. Rich isn't into fish, so I don't tend to look in that direction.
Have a fun time in the city. It's a good time of year to visit!