Hi there,
So the threads you reference are ALL towards the lowest sleep current.
You can do many,many things to use the flash and IMU and still save power, but it up to you to determine which tech ,bsp’, flash sleep, bootloader ,system ON sleep ,etc.is right for your project.
There isn’t a how to on the customized power profiles, you will need to test and measure and reprogram accordingly. Lots of smart folks with experience with the nuance of it. So ask about specific needs and see what comes back
HTH
GL 
PJ 
Using a combination of methods helped me save Mah of battery so try everything