[SOLVED] Cushion as a seat

1. Clone and export the .blend and textures from the cushion.
2. Clone and export the chair (Dining, love seat, meditation stool, etc.) from S4S into .blend
3. Open the chair .blend in Blender and replace the mesh with the mesh from the cushion .blend.
4. Import the modified chair .blend with the cushion mesh into S4S.
5. Import the cushion textures into the new chair .package. (This is also assuming the chair being replaced has the same material properties as the cushion, which may need further tweaking)
6. In S4S, edit the Rig/Slots of _IKtarget_butt_ and _IKtarget_toddler_butt_ so they are lower on the cushion.
7. Shadowmaps of the old chair will also need to be totally removed or replaced with the ones from the cushion.

Don't know how different animation is, but perhaps you could even go a step further and reference the animation for the original kotatsu table in the tuning?
(Not sure of your skill level, and like I said, if it's even needed to begin with.)