i'm having some issues with this jeep i bought for dirt cheap off of craigslist and though of building it some but i am hesitant on starting the project until i get a few issues fixed

1. i know its a ground but this cherokee has had a motor swap and the wiring is FUBAR'D
2.the head lights are just a little dim, though when i step on the gas from a dead stop they flicker, but when i'm driving they're bright enough.
3. the (oil temp, fuel, voltage, temp) gauges are not reading properly when i turn on the lights, the gauges all drop from what they were reading incorrectly