MSP430 individual pin accesibility
1) Yes, you can select pins individually. For example, to set pin 4 of port 1 as output and high:

P1DIR |= (1 &lt;&lt; 4);
P1OUT |= (1 &lt;&lt; 4);


To set the same pin as input, clear the DIR bit:

P1DIR &amp;= ~(1 &lt;&lt; 4);


Even though the P1DIR and P1OUT registers describe the whole port 1 as a whole, the individual bits in that register control individual pins: the lowest-order bit controls the first pin for that port, and so on. Same applies to the other ports, each of which has eight pins.

2) Pins are always "enabled" in some mode. There's DIR flag for each pin (which selects whether the pin is in input or output mode) and there's SEL flag as well (selects whether the pin is data or function mode). The default mode (after reboot) for a pin is data+input.
Energy consumption depends on what you have connected to the pin; there's no single answer.