Does it have a low pressure drop valve in case you get a leak and it automatically shuts off?
This unit has a flow restrictor valve for water flow 300cc. below is the photo of the valve.
There is no pump for this RO system. That means, no power, no low pressure drop valve or high pressure drop valve. there's a valve to control water flow, and hence won't leak. below is the photo of the valve
Does it have a flow restrictor valve which keeps back pressure on the Membrane to make it more efficient
Yes, the wastewater bracket is included in the accessory bag.