@Steve2324 I run my waterfall all winter long and we have many many days well below 0F here in the midwestern US. But a key to whether or not your waterfall can stay on during freezing weather is the construction. Even running water can freeze along the top and edges and the ice that forms can create dams that redirect the water out of the pond. The only way to really know if it will work is to try it and see what happens. But be prepared to shut it down if it looks like you are going have an issue with ice.
As for plants along the liner - they will not puncture the liner, but they can force the liner down and allow water to flow over the edge. Again - watch your pond as things develop and you will learn what may cause you issues down the road.