Answer: Neighbour
Explanation: Taken perspective from the given clues:
The Neighbor walks to work
The Handyman rides a bike
The Cook rides a motorcycle
The Maid drives a car
The Nephew has a dog
If we assume that the handyman delivered the iPad in the mailbox, then
The direction of the cook, Nephew and his dog are perpendicular to the direction of the bike of the handyman. So, it can't be the cook, Nephew and the maid.
The two suspects are the handyman and the neighbour.
If the handyman actually dropped the iPad and left, then, the neighbour should be the culprit.