All been designed in already. With about 2 weeks to go it's not going to be changing. Also, each channel is fully & independently variable from 0 to 100%... so regulation of each would be a little too complicated.
As Mike has talked about on the Amp Hour, considerations such as RFI/EMI rarely come into consideration for short installations (in this case about 50 days) where you may not strictly meet standards. As long as it doesn't interfere with anything used in the nearby area, and it doesn't burst into flames, we should be fine.
Each LED is phase shifted (PCA9685 supports this) so our ripple current is fairly low - should not exceed that of one LED's current, about 350mA. Also, the channels will be soft-switched in a way, because of the weak GPIO drive. We can increase this delay by putting a resistor between the source of the MOSFETs and our circuit & PCA9685 ground, if it turns out to be a problem. The LED current is kept in a separate loop to our main logic power and tied a single star point.
(It's a University project anyway - I've somehow got roped into doing the custom electronics & firmware.)