MacBook: Force hibernation, even on AC power (not battery power)
I've used the DeepSleep app for years to put a Late 2012 Mac Mini into hibernation.  After "upgrading" from OS X 10.11.5 to 10.11.6 two weeks ago, DeepSleep stopped working.  It would only put the computer into normal sleep mode, not hibernation.  I spent a few days communicating with the author of DeepSleep and none of his suggestions fixed it, so I reverted the system to 10.11.5 using Time Machine restore and DeepSleep again works.  So your problem may simply be that you're running 10.11.6.

I have also tried sudo pmset -a hibernatemode 25 on the command line, as well as sudo pmset -a standby 0 and sudo pmset -a standbydelay 0.  None of those have ever made my Mac Mini hibernate when the power button is pressed, even if left overnight, and even on earlier OS X versions.  However, those commands are supposed to work on laptops.  Since you say they don't, that's more evidence that Apple completely broke hibernation in 10.11.6.  However, someone here says they got pmset options to work only after resetting SMC and NVRAM so maybe give that a try.