I'd recommend a bakfiets as option one. I'd stick with either Bakfiets.nl or Workcycles though. The others can be kind of squirrelly. Second choice would be a Dutch omafiets or opafiets (Workcycles, Azor, or Batavus) with a child carrier or a Fr8 or Gr8 with a carrier.

A great blog by a friend and fellow commuter with kids riding around Brooklyn: https://brooklynspoke.com