Sorry but I forgot 2 ask what and where is this Training Dummy that keeps being mentioned?
You can unlock both an Operations Training dummy and a Warzone Training Dummy for your ship through the legacy system.
The training dummies are basically unkillable manaquins that you can beat on forever.
As to gaming mice, you don't need anything particularly special, but the more buttons then the more options you have. I went with the Roccat Kova +
which only has 2 thumb buttons (on both sides in case you are a lefty!). However, after testing a load of mice this was the most comfortable for me, plus the programmable LEDs within it are nice! I'm kinda sad in that I like to colour match my PC peripherals!