Sconces are more likely to combat shadows when you are doing makeup or hair. It is, however, nice to have more than one type of lighting.

Your 150 sq ft bath only needs the equivalent of 225 watts of power. Compact florescent bulbs provide the equivalent of 60 watts using only 13 watts. LEDs use much less power. 4" lights should be spaced about 4' apart; 6" lights should be spaced 6' apart, and so on.

It's more important that areas such as the toilet closet and the shower are fully illuminated. I suggest you center a light in the toilet closet and in the shower. You can also center a light over the tub. One or two more lights should be set to fully illuminate the rest of the bath. I'm sure others would have a different idea of where lights should go.

Unless you are using very small recessed lights there is no need to put more over the vanity. If you do put recessed lights over the vanity they should be 12-18" from the wall. Below is the minimum number of lights I would put in this bathroom. I've also included where switches should go: 1 for the toilet, 1 for the sink sconces, and 1 for the central light and bath and tub light. If you want you can have the sink and tub lights on separate switches. The sconce light should be centered on the wall between your sinks. In the drawing it is off center to show the connection to all 3 sconces. One last thought: consider using a pocket door for the toilet area instead of an inward swinging door.

Thank you mindshift! I'm planning on using the exhaust with the built in light for the toilet room (110 cfm).

For the shower, I was thinking of centering a 2nd exhaust in the middle of it (190 cfm) and have 2 lights in the shower cubicle flanking the exhaust. The 2nd light being over the shower wall near the bathroom doors. Please let me know if the cfm rating seems not sized properly. My current exhaust does a poor job so looking to address this issue once and for all.

I'm hesitant about the light directly over the tub (staring into the glare while in the tub). Instead, just hang the chalendier in front of the tub or in the center of the room.

Love your ideas for the switch positioning. Thank you for your insights especially for the overall wattage needed for the room!

I'm sorry rashmi, but I am not a professional so I can't advise you on cfm. I have done my own remodel/addition, so I know something about the design elements and practical application. Whenever I'm unsure of something I do a search. As to lighting position, I thought all of your lights were recessed. If you intend a chandelier then centering it makes sense.