The solder mask is a bit difficult to see through, my apologies.
Here is a key photo:

Here is a a video of the whole boards (1 with the capacitor still on, the other with them removed):
https://youtu.be/gSdic5ZpIjUHere are photos of the the power supply shipped with the unit - it is being replaced.

Sorry, I omitted the readings across the component. I get a transient spike of +/- 0.007v at power up on the circuit, then it stabilizes to 0v. I am powering it directly with a constant current bench supply.
As to the function, at the end of the second board it uses a common +, power supply (should) allocate 0-100% on one set and 100-0% on the other - so yes they can both be on at the same time.
The commercial specs are (if you want to google the product):
Tunable White LED Panel Light - 2x2 - 4,300 Lumens - 40W Dimmable Light Fixture
Part Number: LPD-TWR22-40
CRI 80 CRI
Current Draw 0.33A (330mA)
Efficacy 108 lm/w
Intensity 4300 Lumen
Total Power Consumption 40 Watts