Bathrooms
Bathroom fixed loads like lighting and fan can be served by any convenient circuit.
With the bathroom receptacles, you have two choices.
- Many things, one bathroom: The circuit serving receptacles in one bathroom can only serve other loads (fixed loads, lights, fan) in that same bathroom. or...
- Many bathrooms, only receptacles: A circuit may serve receptacles in any number of bathrooms, but it can serve only receptacles and only in bathrooms.
You can go either way.
Switched receptacles
When having split receptacles (one unswitched, one switched)... the usual way that will be most understandable by "the next guy", and keep box fill sane, is to do switched receptacles is off the same circuit that powers the unswitched receptacles. So in that case, you connect 12/3 between the two split receptacles, and from one split receptacle to the switch. Remember, you need to carry /3 to a switch loop because you must bring neutral in a switch loop. You cannot use neutral from the other circuit!!!
Because you will have two different circuits in the same box, you must be very careful not to mix them. You might even consider putting this switch in a different junction box, to remove all risk of confusion.
Having made the /3 connections between the two receptacles and the switch, you now can supply power in any of these locations - or really, anywhere else in the circuit. Since I would be worried quite a lot about box fill in switch #1, I would consider feeding power into the receptacle circuit at the near receptacle.
Off the far receptacle (or anywhere in the circuit), you then continue with 12/2 cable carrying always-hot and neutral to other outlets.
The second way to do it is to put these switched sockets on the lighting circuit. In that case, the switch box would be all one circuit and that would ease box fill there. But now you are running two complete circuits to the switched/split receptacles, although you can use /2 cable. You will need to break off both the hot and neutral tabs and take care to keep separation of circuits. Which will make box fill worse at the receptacles.
Closet lamp #4
Given the proximity of closet lamp #4 to a receptacle location, consider powering closet lamp #4 off the receptacle circuit instead of the lighting circuit. This will need #12 wire because ALL wiring in a 20A circuit must be #12, no exceptions. It is totally legal to do this, it's just not recommended to put lighting on receptacle circuits generally, because if you overload a socket, the breaker trip will plunge you into darkness. That's not a big issue on a single closet.
By the way, no receptacles allowed in closets, and lamps can't be where clothing can touch them.
Box fill
Switches 1 and 3 are going to have a rather significant box-fill problem. I believe we discussed this six months ago on the three-fan circuit. Be careful selecting your boxes so they are large enough, I'm fond of 4-11/16 square steel boxes and either 1-gang or 2-gang mud rings.
Here is a diagram that represents what you want to do:
Run a 12/3 from the fan/light combo to the 3-gang, and a 12/2 from each light to the 3-gang.
I have not drawn the fault ground wires into the diagram. You will have a bare or green wire from the power feed cable, bare wires from the 12/3 and 12/2's, a green wire from the DVFSQ-LF, and green screws on each of the simple switches. Connect them all together. Don't let them touch any of the terminal screws on the simple switches.
In the fan/light combo box, connect the red wire to the fan, the black wire to the light, and use a wire nut to connect the white neutral wire to the neutral connections on both fan and light.
In each light box, connect the white wire to the neutral side of the light and the black wire to the hot side. If the lamp wires are not marked, the neutral side of a lamp is always the connection to the threaded part, and the hot side is the metal button at the bottom of the socket.
In the 3-gang box, use a wire nut to connect the neutral wire from the power feed cable to the white wires in the 12/3 and the two 12/2's. Use a wire nut to connect the hot wire from the power feed cable to the black wire on the DVFSQ-LF and to the line terminals on each of the two simple switches. The terminals on a mechanical switch are interchangeable and usually not marked for line and load. Just choose.
Connect the yellow wire on the DVFSQ-LF to the black wire in the 12/3 cable. This will control the light in the combo. Connect the red wire from the DVFSQ-LF to the red wire in the 12/3 cable. This will control the fan in the combo. Apparently the DVFSQ-LF has no screw terminals so you will need wire nuts for these connections.
For each cable from a light, connect its black wire to the load terminal on one of the two simple switches.
As discussed in the comments to the linked question, you must add up the amperage of all the lights and fans, and make sure that the number is not more than 80% of the circuit breaker rating.
Best Answer
If I understand your layout, you could wire it like this:
Chaining to all four lights like this requires the use of 12/3 cable for the first two sections, but if you want to follow Tester101's suggestion and add the extra conductor to the fan circuit for possible future use, you're going to buy some 12/3 anyway.
EDIT: Carl Witthoft is correct, the bathroom should be protected by a GFCI. I have altered my diagram to show a GFCI outlet with downstream protection.