“City Hall?”
You and hubby can take care of the paperwork during sheva brachos.
As for the ceremony, I was thinking along the lines of Prospect Park, or the Bklyn Botanical Garden (I think Wednesdays are free admission to the Garden)
No doubt one of the dates were there, so its got sentimental value.
OTOH, I hear Ateres Avrohom has a killer shmorg!