So my one and only problem now is that my reverse light doesn't work. I have a volt meter connected and when reverse isn't engaged 0volts, when engaged 8volts. I know it's meant to be 12 since I tested my rear fog and it works perfectly at 12V. Any ideas?

hmm..
1. check on the gearbox. there should be a "reverse switch", you can put the multimeter on that ( set it to "ohms" ) and see if the reading shows 0 ( zero) when in reverse.
2. those 8 volts can be either be a sign that there is a short-circuit somewhere, or it could only show 8V when not under load..somesort of induction voltage ( i don't know the correct name for it). Test it with a load ( get a good bulb, connect one terminal to the 8v wire, and the other to the ground on the car's body, now connect the multimeter and see if there is still voltage )