In addition to the other good ideas here, there is a lot of expertise about schools generally, and the lottery in particular, on the cpsparents email list. You can get some info at https://cpsparents.groups.io/g/main or just subscribe via email to main+subscribe@cpsparents.groups.io. It's been quieter lately but this is just the kind of question where the wide-ranging membership there will likely have useful comments, both about the lottery and specific schools.

I would not say above / below. They're different kinds of places. Flour is far newer (opened in 2000), fancier, pricier, does a lot other than pastries. Lyndell's is much older (opened in 1887), traditional, less expensive, focused on pastries, and pretty high volume. Both are good but if I had the OP's needs I would choose Lyndell's. (Royal Pastry is also an older, more traditional bakery similar to Lyndell's in style.)

I don't think it reverses flow during typical flood events -- only if the Amelia Earhart dam in Everett is overtopped by rising sea level / storm surge, which would make the Mystic River flow in reverse.