Be really careful with those antique cloth covered wires. The cloth insulation can start to fall apart very easily and leave exposed wire when you try and push it back in. Judging by the one wrapped in electrical tape that might have already started to happen though it might have been done to mark one wire as a hot lead.
One option might be a POE to 12/9/5v convertor like this. I use one to run a 12v non-POE switch up in my attic from a basement POE switch.