Would future firmware updates be a possibility? Not on the production light, of course, since I guess we are too far into the process to make such a huge change, but as a DIY updgrade?
Yes - 2 screws to pop out the driver, need a download cable, 8 pin clip, and USBAVR adapter. Download the HEX file
What is an LDO?
Low Dropout Regulator: we use it to drop incoming ~8V from two cells in series to under 5V to power the MCU. Could be used for 4S input as well (~16V).
3 channels already existed on the H17F driver, but I don't think DrJones released the code, did he?
No - Dr Jones doesn't provide source code to his main line firmware versions he sells, but he was instrumental in providing one of the original sample source code drivers