[Setsback]

The previous owner removed all the lights and cut the wires going to them back to the harness and made a hell of a mess of the electrical

My question, would it be easier to install a new wiring harness/Loom or salvage the old one.

 

[flitecontrol]

I would go with a new or used harness, depending on what model year Rebel you have.

 

[SoakedKarma]

Depends on where wires cut at..
all lights have junction boxes that lighting connector leads plug into..
front junction box behind headlight while the rear box is part of taillight/license plate mount..
if light leads were all that was cut you should be fine just replacing lighting fixtures..
if main harness damaged I might replace entire wire harness

there is a sub harness that runs from under seat to rear junction box.. All years 1985-2016 use the same rear sub harness..
85-87 and 96-2016 main harnesses are very different and not interchangeable.