If the strip can be powered by USB, then it draws little enough current that you can power it through the pi.
I'm not sure what you mean by driving them individually. Do you mean each color individually? The LEDs will be arranged in parallel on those strips and so there is no way to address one specific light within the strip. You only have control of individual colors.
Connect 5V to the 5V pin, then the difficult part is that you will need to connect each of the other pins individually to GND. When you connect each of the other pins to GND, you will individually switch on the colors. G for Green, R for Red, and B for Blue.
Of course, you cannot sink those through the pi's GPIO's, not only because the 5V will murder your pi, but also because the current that you need to sink is FAR GREATER than what a GPIO can handle. So you will need 3 N-channel FETs, and 3 resistors around 10k ohms. Connections as follows;
S --> GND
D --> LED strip color pin
G --> Some GPIO on pi
G --> Resistor --> GND
When you switch on the GPIO pin, it will activate the FET and light up the corresponding color on the light strip.
You can also use PWM to control the brightness, and in this way, individually control the brightness of each color, which gives you the ability to set the overall light color, as well as the overall brightness.