A Little Short For A Stormtrooper is one of the many trophy achievements that players can unlock. It can be unlocked whilst on the Boarding Party mission
In order to unlock this trophy achievement, you will have to create 25 disguises as a Hero Character
For this specific trophy achievement you will need to change at least 2 Hero Characters and have them change their costume disguises.
Each time you change costumes it will count as having changed a disguise at least once. We need to change into disguises a total of 25 times, which seems a lot.
However, the good thing about this one and to cut down on time, you actually only have to find one costume disguise. Meaning you do not need to go through the game and find different ones. Using the same disguise over and over, seems to actually work. As has been proven with the video posted above (Thanks to: Trophygamers)
As long as you have 2 Hero Characters available to you and are able to swap between them both, all you have to do is play on a mission that drops a costume disguise. The Boarding Party mission for example, is one such mission. As you can find the Stormtrooper disguise during this one.
Simply switch to a Hero Character, does not matter which one, then play through the mission until you come across the available costume disguise. From there equip the disguise, this should include the leggings, boots, torso, and helmet. This will then pit you in the full Stormtrooper disguise, as required.
Once one character is in full Stormtrooper gear, switch them out for the next Hero Character and repeat the same process. Do this 25 times to unlock this one.
As said you can find the Stormtrooper disguise during the Boarding Party mission, when tasked with ‘Finding a way to get the Death Star plans off the ship’