The electrician is putting several different switches in the LR, so I'll make sure he does the same in the kitchen. Here's another question. I hate the light my current overhead fixture gives off. It's worthless. So I doubt I would even use an overhead light. However, should I still install an overhead fixture just to make the room look better, whether I get the green fixture or not? Will the ceiling (8 feet) look strange without a fixture?

That does seem like a viable option. Would a single pendant be sufficient? If the sink is the dark spot, I think it would. If it is that whole end of the island would you consider a track or monorail system. It could run on one side of the sunlight, or all around the perimeter. Different heads in different spots for task lighting, or to create an ambient up light too. I am pretty sure with tech, the box can have 2 switches, so you can turn on just the task lights, just the ambient lights, or both.

Wire it up. The "future" cable will need to be connected to a breaker if it isn't already. Make sure the connection from the "future' to your new switch wiring is in a box.

You are correct that one wire is hot. Still don't have it working since I have only 4 wires and Cooper Wiring's diagrams all have 5 wires. Their advanced wiring diagram which is for the lights located between the 3-way switches shows two sets of 3 wires (this is what I have in the garage), and I only have 2 wires other than the ground wire at one of the switches. Tried to reach their tech department twice, but received no response. I'll attach a diagram of the wiring. One of the black wires in the earlier photo should be red since it's connected to a red wire in the junction box. To see their wiring diagrams, Google: Cooper Wiring OS310U, then click on each of these selections: Single Occupancy/Vacancy Sensor Instruction Sheet (English), OS310U & VS310U Advanced Installation. Hope you can help me find the right way to install the sensor.