AFAIK:
1. If no lighted switch there should be no parasitic drain, but Li-Ions can discharge just by themselves. However for 18650s it should take more than a year
2. The driver has it’s own protections including heat, polarization and over-discharge. Using two protecting PCB (driver + the cell) may not work properly. I’d recommend to stay with unprotected ones because: a) you already have it incorporated in the driver, b) protected cells are longer and may crush the springs (or even the driver)
3. The light will blink to inform you that the cell’s voltage is at its minimum. With the FET driver (I believe you have the one) you’ll aslo notice brightness loss.
4. There is no just bliking mode. Those available to choose from are:
1. 0.1, 1, 10, 35, 100%, strobo, biking, battery-check
2. 0.1, 1, 10, 35, 100%
3. 100, 35, 10, 1, 0.1%
4. 1, 20, 100%, strobo, biking, battery-check, SOS
5. 1, 20, 100%
6. 100, 20, 1%
7. 0.1, 1, 10, 50, strobo, biking, battery-check, SOS
8. 0.1, 1, 10, 50
9. 50, 10, 1, 0.1
10. 1, 10, 35, 100
11. 100, 20, strobo
12. 100%