Rig & Animation Help?

Is there a way to set up a rig so that whenever all keyframes are deleted on a certain frame, all the bones without keyframes go back to their original positions for that frame? Meaning, for example, if I delete all the keyframes in an animation, the rig automatically snaps back to the T-pose I gave it when I built it.

Also, how do I prevent keyframe edits from overwriting keys other than the one I Im currently editing? When I edit keys, the changes end up applying to all keyframes before and after the one I meant to change, and I end up having to go back to those other keys and manually reset them to where I had them before I made the edit.

Automatically? No. Easily? Yes. Delete keyframes. The, select all, alt r, alt g, alt s. Then, advance a keyframe.

Keyframes don’t apply to earlier keyframes, or to later keyframes. But if you only have one set of keyframes, there won’t be anything to interpolate between-- it will just be constant. If you want to interpolate from rest pose, to keyframed pose, to rest pose, consider keyframing all bones, in rest pose position, at the beginning and end of your animation, prior to making any keyframes. Hey, if you forget, no worries: go to beginning/end, select all, alt r alt g alt s, keyframe loc/rot/scale.