I'd go with the Lezyne.
Lots of features, and good reviews. Having a young child, I think the ability to read text messages while riding would be very nice.

I wouldn't worry about the cadence sensor thing. That's the whole point of standards. Very likely Lezyne just hasn't specifically tested against a DuoTrap. They have tested the DuoTrap S and it was compatible.

If all else fails, buy from somewhere with a good return policy and return it if it doesn't work with your sensor.