A question for customizers from someone who has no customizing experience.

How feasible is it to pop off the heads of Starfleet characters and swap them for 7" heads from other toy lines? Primarily TOS; I was thinking of getting a couple "Tribble" O'Brien redshirts, not to mention reusing some extra Kirk/McCoy bodies.

I have not worked in this scale but head swaps are one of the easiest customs you can do, the other being a straight repaint. I prefer the smaller scale. I will usually nuke a cup of water for about 3 minutes then drop the figure in it so the part I want to remove is submerged. The heat softens the plastic. Pull it out, grab the head and pop it off. You may want to return it to the hot water before mounting it on the other figure.