Thank you @paul-thornton, I just saw the addition to the web page with the mechanicals. I'll start drawing my board ;)

@thosch42 The LED is indeed connected to P2 = GPIO0.

@ssmith Yes it's perfectly fine. If you measure at the 5V pin while powering from the 3.3v you'll see the voltage minus the minus the internal diode drop of the high side FET (should read about 3v or slightly less). I wouldn't recommend leaving other devices attached to 5V pin as they may be powered by that backfeed through the diode and potentially overheat it, but I don't see a problem to leave it floating. There may be some very small extra consumption (a few μA? I'd need to order the TI eval kit to be sure) caused by this so, for optimal power consumption, you really should go plan for the L01 OEM module soldered on the PCB.