Hi,
If you are going to using free-standing units and applicances, I think that
the floor has to go down first.
What sort of sub-floor do you have - concrete, or old floor boards ?
Is it flat enough to put applicances and units straight onto.
I think that putting the floor down last only works with a completely
fitted kitchen.
If you put the floor down, everything sits on the same floor and and small gaps between units will have the same floor.
If you put the units and applicances in first, the flooring will have to abut to the front of all the different units and appliances and I dont think it will look good, and will take away from the style of kitchen which you are describing
I