Light fixture, power source and range vent fan & light wired together?
The green wire nut with the hole in the tip is normal.  Green wire nuts are the same size as red, except they have a hole in the tip.  That's why they're color coded green, to tell you that.  And they're for exactly that use. 

All ground wires should be connected to each other, and also to any appliances or devices and also the metal box if metal.  

The switch is what's called a switch loop.  It's an older style one with /2 cable (black, white) and no red.   In a switch loop, the white wire should be used as always-hot and tied in with the blacks.  The white wire is chosen to be always-hot so it's more obvious when you're checking it with a voltage tester.   It should also be marked with tape to indicate the white wire is a hot, this step is often overlooked. 

It sounds like the other cables in the box carry onward power to other devices, e.g. the hood.  

It would help to have photos of what is going on in those boxes.