/diy/ - Do It Yourself

>>2035012
I don't fully understand your question, but I hope this helps you understand what you're looking at doing. The cord you salvaged is type SO cord, which may or may not be the correct gauge you'll want. As you are splicing them to existing romex, which uses solid 14 or 12 gauge wire, I would suggest finding or buying romex to finish this project. Romex is slightly better protected (sheathed) which is good here since you're doing some ghetto rigging (open air splicing out of a box), and solid wire is much easier to splice to solid wire. As you seem new to this, use a pair of pliers and mechanically twist the exposed wire ends you're slicing together before twisting the wire nut on, and tug each wire coming out of the nut to ensure it has a good connection.You may want to use a few big blue wire nuts at the junction point where a light, switch leg, and other fixture feed meet. Do not use wagos. Also, you don't need to have the sheathing ripped off of the wire between lights.
As long as you don't tie a black to a white wire, the colors in the picture don't matter. If you just leave longer whips of wire hanging out of your wood holes, you can get to sheathing your box in the oak ply and having it all prettied up before throwing in the lights. Leave the wires a foot longer than you think you'll need, and stuff it up in there after you trim out the lights. Don't forget to tie all grounds together as well (not included in pic).