It's not per die.
In electronics (regardless of the component) you have voltage and you have current (measured in amps). In this case, the components are LEDs.
If you wire the LED dies in series then voltage is split between them and you want to make sure that the voltage provided is enough to supply all of them. In series means that you wire from one die's positive to the next die's negative. (example wiring: board- to die1-, die1+ to die2-, die2+ to board+)
If you wire them in parallel then the current is being split. In parallel is how yours is wired. From the board+ to each die+ and then from the various board- to each die-.
So your 2A are being divided six ways. Split evenly, each die would be getting 333.33... mA. Adjusting current to each die is how color mixing is achieved. The more current, the brighter the output of each die. Again, assuming that you're going for some particular color that's not whitish, then you're not splitting evenly - how much each die actually gets depends on what color you're going for. Unless your board somehow has multiple individual LED drivers built into it then that's the scenario you're looking at.
(idea: wire each like color die in series. That will add wiring back and forth between each end of the saber. So each like color pair would be in series making 3 groups and those 3 groups would be in parallel. The net result would be that each die would be sharing current with its counterpart but splitting voltage. I have totally not even tried to work out the math as I don't know what the max voltage provided by your driver is)
The above is not relevant to Darth Ryo's issue for reasons stated below but is retained for any informative value.
Regarding the space issue (act. box, switches).... I have to resort to guessing here but if that's a short momentary and if the Igniter is as thick as I think it is then you *should* be able to but just barely. But not having handled one physically I'm not sure what its thickness is.
Edit #2: Ok I feel like an idiot now. Apparently that's what the TruColor addon is; another two constant current drivers to drive the other two dice at full current. Sorry Ryo, never mind what I said before, should work out fine exactly as you have it in your diagram aside from your battery lifetime. The current IS split in parallel though so whatever you configure for each die will be split in half. The other thing I said about it setting each color by adjusting current also seems to be wrong so I guess it's adjusting brightness by PWM.... which is pretty sweet.