I'm pretty sure the BQ24195 is in the lowest power mode in SLEEP_MODE_DEEP or SLEEP_MODE_SOFTPOWEROFF however there are so many settings I can't guarantee that.
(SLEEP_MODE_SOFTPOWEROFF is SLEEP_MODE_DEEP but also turns off the MAX17043 fuel gauge.)
You will definitely get the lowest power consumption using Li+, assuming you can provide an acceptable voltage level. The reason is that when powering by VIN the voltage regulator is always on. When LI+ is in an acceptable voltage range, the regulator can be bypassed. It's only possible to get to 110 uA in deep sleep when powering from Li+.
This post may clear up some confusion about how to get into the lowest power mode, as various combinations of threading and system modes can prevent it from working properly: