In what country are you building this house? 9 foot or vaulted ceilings are taller than the US builder average of only 8 feet (this is the distance from the ground to the ceiling). If you have a small room, having a higher ceiling (even only 1 foot extra) will make the room feel more open and airy. In a small house of 1500 square feet, having high ceilings would go a long way in making it feel much larger than it really is. It is especially beneficial in a hot climate because heat rises so you will spend less on cooling costs. It is not so beneficial in a cold climate. It still looks nice, though!

I like this tile as well. Very sleek and mod looking. I would consider running it vertically instead of the picture horizontal pattern. It might give the illusion of more height in the shower surround. The color is great. If you are worried about it being "too much," you could always see if they have the same tile in a different shade and mix the two or doing one wall in a contrasting (lighter) color. I personally like it as long as you have good lighting.

Effectiveness is influenced by capacity of unit. If you are trying to mount a 270 cfm fan more than 30" above cooktop, then it may make noise but will do little to clear the air. If it is 1000 cfm, then it can be higher than 30". So the answer is "it depends". Most people don't mount them more than 36" above the cooktop unless it is a really high powered unit.

The island works in the plan provided, you might even make the island longer. 42" clearance will work between island and cabinets (36" if not much trafic, and no appliance door swings).