This can be done probably easiest with a micro-controller but since you say you don't know alot about circuit design, you should probably go a different route.
First off, the 2 outlets that need to be on continuously don't need any modification. They will just be wired like normal outlets.
The other 4 outlets that need some kind of control can be switched on and off with a circuit like this:
SimpleIO - Application Note - Triac Series Gate Resistor
The component marked "T1" is a triac and in order to select the appropriate triac for the job, you'll need to know how much current whatever you're switching on and off will draw.
The next part of the design will be the input into the opto-coupler/triac circuit.
For the temperature controlled outlets, you can use a tempo sensor with an analog output. You'd then feed that analog output into a comparator which would in turn output to the opto-coupler/triac circuit and enable the AC outlets. Read this about temp sensors:
Temperature sensor tutorial - Using the TMP36 / LM35
For the outlets that turn on at dusk, you can use a light sensor in a similar fashion to the temp sensor. A light sensor like this:
SparkFun Electronics - LilyPad Light Sensor
will output and analog voltage based on the amount of light. You would feed the output of the light sensor into the input of a comparator, when the voltage drops below a certain level (i.e. the light level drops) it would turn on the opto-coupler/triac.
The 4hr timer or dawn portion can be handled a few different ways. Maybe someone else can chime in on that or you can just digest and make sure you understand everything so far. Hope this helps get you started.
BTW, you said you want the dusk enabled outlets to turn off after 4 hours or at dawn, whichever comes first. Out of curiosity, where do you live that dawn occurs less that 4 hours after dusk?