Say what!
A reputable contractor would never ask such a thing. They would have a rent a toilet delivered, charge it to you, and provide their own drinks.
Were he to be on the up and up, he would provide you with a bond from his bonding company should anything come up missing from using these hands he "finds". These unknown people will be walking down your hallway past your valuables?
Sounds shady to me. I'd be looking for another contractor.
Steve