cat makes some really good points.
I've been considering a cargo bike, the Lectric Expedition, thinking about putting my daughter on the back, but she told me the other day she'd rather ride her own. Even at 5 or 6, she'd probably have preferred to ride her own.
I think you'd be better served by an XP 3.0 with the cargo package, unless you have a minivan or something where you could just fold down the bars of an Expedition or something.