Can you reset the SMC an all Mac laptops by pressing power for 5 seconds after disconnecting the battery? I've always had this doubt and some clarification would be very welcome.  On Mac notebooks with non-removable battery (such as the MacBook Pro 2014), is the SMC reset by disconnecting the battery and pressing power for 5 second as is done on older Macs with removable batteries (such as in cases where Alt or Command keys are not working).  

Here's the Apple article on SMC reset:
https://support.apple.com/en-gb/HT201295
No, on Mac notebooks with non-removable batteries you "press Shift-Control-Option on the left side of the built-in keyboard, then press the power button at the same time. Hold these keys and the power button for 10 seconds", exactly like stated in the support article you linked.