i think only druids are able to choose natural spell (feat as a druid) meaning, even if you got wildshape/4th druid spells, you won't see it listed on shifter..i think @@
as for using the feat, yea, pnp shifter is able to use it, tho he dosn't need it for ALL his shapes, some creatures don't need it, but it's safe to take it.
pnp shifter use a different dilogue system, different from misc one, but similar, each level you get to select a new shape from packages (you specialize later in one, ie: undeads, outsiders, dragons etc ..) ..you cna also use the feats coming with class to shift into any creature you see
... just try the class, it's addicting *_*