Applying two animations?

Is it possible to apply two animations to an object. For example: a character bottom half animation, and top half animation?

If so, what would be the best way to achieve this?

I would suggest using Unitys avatar masks and animation layers in mecanim. set up the base animations on your base animation layer and on your second layer apply the avatar mask so only specific joints play animations from those animations.

I think you are looking for AddMixingTransform and this answer might help you:

Using the legacy animation system, use Animation Mixing.

Using Mecanim, create two Animation Layers – one for the lower body, one for the upper body. Apply an Avatar Body Mask to the upper body layer.