add stealth mode to non tactical version

No

Dan.Boilermaker is right, but you could use the Battery Saver (or even a Power Mode of an activity) to mimic the stealth function to certain degree - disabling sensors, BT, GPS, backlight, ... Not sure whether it can work to the full extent like the stealth mode, but it is probably the best alternative you have.  

trux said:

to mimic the stealth function to certain degree - disabling

trux said:

GPS

Stealth mode does not disable GPS. GPS continues to work, but the position is not saved.

Thanks, not having the tactic model, I do not really know the mode. However, you can configure the Battery Saver (or a Power Mode) so that it keeps GPS on. You cannot turn off position logging, though (as long as you use an outdoor activity profile)