The only way I know of to have both the fan and light to come on together would be to wire them together to one switch or timer. I find it very easy with the stacked switch to hit both buttons when I enter the bathroom; I turn off the light when I'm done in the shower, and the fan turns itself off after an hour (or whatever time you set it to). If you wired them together to a single switch, then you wouldn't run the fan after the shower, which is good for drawing moisture out of the room. If you wired them together to a single timer, then they'd both be on for an hour until the timer shuts them off, wasting power on the light for an hour every day. (Depending who's using the bathroom, you might also have someone turn off the light, not realizing it's also turning off the fan.) I'm sure someone with an electronics background could build a box you could stash where the wires run in the attic with a relay that turns the light on when the fan goes on (or visa versa), but doesn't turn both off when the switch goes off for either one. But I'm not aware of a readily-available commercial switch that does this. -- Eric

I don't think you will have to worry to much. You could do 3 or 4 light and would be fine. I had been shopping also for a new light fixture and looking for ideas online I had even seen vanities with a single light light fixture and you would think it would look odd or undersized, but it actually looked fine.

You have a lot of options. You can install a narrower framed mirror above the sink area, then install lights on each side. Outlets can go either above or within the backsplash. Another option is to do a large mirror with the outlets on top, along with your lights. My previous MB had a large mirror above a 6' vanity. Both lights and outlets were on top of the mirror. Another design would be to add a small cabinet on one, or each, end and put your outlets there.... As for hiding the outlets with a moveable mirror, I think it would not make for easy access to the outlets. Especially if you're going to use them for charging toothbrushs, shavers, and running hair dryers. Here is a link that might be useful:

This article gives various suggestions for how to remove the logo or other printing from the base of a light bulb. Knowing you can remove the printing could widen your search results! www.houzz.com/discussions/2668497/removing-printing-from-the-end-of-light-bulbs