I have an existing 3 way setup, with a switch on either side of the bed.  I have an empty bay in the switch box by the door and would like to add a switch that controls that setup. Please note, that is powerd by a GFCI in the bathroom.

We want the new setup to have dimmer controls at each (now 3) locations with dimming and on-off functionality.

1) Is this possible by having the switch at the door control the existing 3 way only with smart actions (no added wiring?)

2) Will a properly wired GFCI get triggered from a kasa smart switch?   (Only asking due to posts where other users had issues)

Thank you for your help.