In particular, they ll be operated with PWM (80Hz, 5% duty cycle).

@user The datasheet for the laser would help here. Post the link, please.

one thing to note is they will consume more than 5mW each, that's the optical power. usually the actual power driven through them is like 2-5x higher depending how efficient they are.

How precise in voltage/drive current must you be? any optical or performance specs you are meeting? That will dictate how you control them and how precise the circuits need to be. If it's not really an important factor for their output precision, you can look at doing a low-side N-channel MOSFE load switch which is driven by your PWM signal