Hey that's awesome!
I've looked at a bunch of apps on the playstore and so far no free one would allow me to replicate the navigation bar while switching the action. I would appreciate the mention of one I could use for this. (Unlike One Button or Pie, I wish for standard buttons).
Not exactly what you asked I know but this one works pretty.
Swipe the edges of your device to do many useful actions.
I've set Swipe from RightEdge -> Back
Swipe from Left edge -> Google Now
Swipe Up -> Start Lawnchair
Far Swipe Up -> Recents