Step 1:
System Preferences -> Mission Control
Change "Show Desktop" to F10
Change "Show Dashboard" to F11
Step 2:
System Preferences -> Keyboard
Click "App Shortcuts"
Click "+" symbol to add new
Leave Application as "All Applications"
Type in Menu Title exactly this phrase (without quotation marks): "Shut Down..."
Click cursor in the Keyboard shortcut field, then on keyboard hold "fn" key then select "F12" on touchbar
Result:
Holding "fn" key and selecting "F12" on touchbar will bring up the shutdown prompt.
Holding "fn" key and selecting "F10" will show desktop, holding "F11" will show dashboard.
<Edited by Host>