Are additional smoothing capacitors required off of a voltage regulator
Smoothing caps need to be as close to the power pins as possible of the target ICs. Trace parasitics add a whole bunch of invisible components in series with the power and return nets. It's a difficult concept to visualize from a schematic standpoint, since a schematic shows logical relationships (nets) but not physical relationships (how far apart parts are, how convoluted the routing is, etc.)

Unless your PCB layout is such that the regulator, capacitor and power pins are fractions of a millimeter apart, you'll need the local capacitors.

As a rule of thumb, it's always best to add decoupling everywhere you think you may need it on a layout - it's easy enough to not populate parts later, and much harder to add a cap where there isn't room for it.