I'm pretty sure this is all fine, but I just want to get a second opinion. The guy at home depot didn't seem overly confident in his acceptance of my plan.
I bought a TV for the bedroom and wanted to mount it on the wall. There were two outlets along the wall where I was mounting, and the mount happened to be directly above one of these outlets. I decided I would just run a recessed outlet behind the TV that's passed through the outlet below. Easy! I've done this several times before...
What I should have realized is that the outlet would already have wires passing through.. down to the next outlet along the wall. I could pig-tail it in, but I didn't know if I could have 3 cables going into a single box safely. I also couldn't feasibly fish the cable up to the recessed outlet without putting two cables through one hole in the top of the box, and I knew that wasn't a good idea.
I ended up ripping out the single box and outlet, replacing it with a double box, then just pig-tailing 3 white, 3 black, and grounds. So I essentially "moved" that lower outlet so it's now the recessed outlet above. All pig-tails (3 total mars connectors) are shoved into the double box, and there's a plain plate screwed on.
One probable issue is that since I didn't actually open the wall I wasn't able to properly tack the new wire to the stud, so it's loose. I'm not overly concerned there since it's about 3 feet, I left some slack, and the wall it shares realistically won't be nailed or drilled into by mistake or anything.
Am I missing anything?