I don't have P5, so can't comment on P5 specific features. My understanding is that morphs work by moving vertices, there is no finer level.

Anim8tor is a free modeling app, that I have heard good things about, another free one is Metasequoia. There is a commercial morphing utility called Extreme Morph 3D, that you might want to look at, I think is on sale now for around $50.00, I have never tried it myself, I think there is a save disabled demo so you can try before you buy.

http://innuendo.ev.ca/extreme_morph_3d.htm