How do you animate unconventional / non-upright poses (using a Rigify rig)?

Rigify to me seems best suited for “standing” actions like walk cycles, gun aiming, sword swinging, etc. It’s best for these because the pelvis is the root-most bone.

However, I go through a lot more trouble animating other non-upright poses, for example lying on the back then rolling onto the front. It’s more like the middle of the torso should be the root and the pelvis and chest can be controlled independently. Instead, adjusting the pelvis adjusts everything and you have to reposition the chest. (I hope this makes sense!)

How do you usually animate poses like this? I often duplicate the spine bones and reverse the bone order or do an IK setup for example, but I’m not sure if I should be doing it like that. Do you preserve the entire rig and animate as-is, do constraint setups using empties or curves, or something else?

Each radically different type of action, IMHO, would get it’s own specialized rig rather than adapting a single rig to do everything. If the centre of gravity needs to be the chest or left elbow or whatever, I’d create the rig with that in mind. It makes my head hurt just thinking about it, but it’s the first approach that comes to mind for me.