Looks like I’ll be answering my own question, in case someone else new to the DragonBoard 410c happens to wonder about the functionality/use of the BT and WiFi LEDs they won’t come-up empty handed when searching (like I did initially)
On the board I ordered from Arrow (the Amazon IoT/AWS package) Android was not pre-installed, linaro-alip 4.2.4 was installed (the version at this location: http://builds.96boards.org/snapshots/dragonboard410c/arrow/debian/23/)
As mentioned, other than a brief flash of the BT LED at power on, nothing happens with those two LEDs.
It seems they are assigned in the same manner as the other ‘user’ LEDs under Linaro and their trigger is set to ‘none’ (via /sys/class/leds/apq8016-sbc:yellow:wifi/trigger and …/apq8016-sbc:blue:bt/trigger) for each LED so no activity will occur on those two LEDs by default under Linaro in the release mentioned above, at least.
If you want one to show when packets are received on the network interface you can execute (as root or via sudo) ‘echo phy0rx > trigger’ from within the directory shown above for whichever LED you choose. Run a ping or whatever you like to generate some traffic and you’ll see the corresponding LED blink when packets are received. The trigger change does not persist across reboots and this is about as far as I went with it. I did not see a trigger listed that would activate an LED when there was activity on the BT radio and didn’t investigate that any further either. I mainly wanted to ensure the LEDs on my board worked and whether they should be doing anything by default.