I want to apply a partial pose- to V4's hips and legs, while leaving the rest of her as is. Is there any way to do that?

Unless you find an actual set of partial poses that are what you want, the only way I know to do this is to pose the specific body parts the way you want them and then save out your own partial pose. I don't know if there's a way to apply a fully-body pose only to specific body parts.

When you save the pose click select subset, click universe box to clear scene hierarchy, click just the hip and all involved leg actors you want included and save the pose. Include morph channels will include any current dialed morph values and apply to the figure if those dials are present. Body transformations will include any rotations/translations applied to the body actor.

Using select subset will create poses that effect only the selected actors, regardless of what's going on with the rest of the body parts. Being that transformations to the entire figure can be derived from both the hip and the body actor, it's something to keep in mind.

Or if you have LM2, it is one of the provided functions to use any pose and apply as a partial pose

Bill

IIRC, there's also a Pose Manager for V4, or some such, that affords one the same capability. It's not as easy to use, I wouldn't think, as "Library Manager 2", though.