rear brakes-ABS-blah blah blah

[dksob81]

Ok here it is, my Father -in-law, ahs a 98 olds achieva 3.1L

he had one of his dumb ass friends changed the FRONT brkae I repeat FRONT brakes. well when he came back that night, I took the car to run to the store, and the brake pedla vibrated real bad, and it feels like the back brakes were grabbing -when u would come to a stop and then continue driving (like come to a stop and then go) the back end would pop up, like the brakes were sticking. if u stopped for a couple seconds it was fine, it was just quick stop and go it would pop up. well I fixed the front brakes and now the pedal is fine, but I couldn't think of anything that he could have done to the front brakes that woudl affect the rear brakes. well a couple weeks later, i decide I would take the drums off and inspect the brakes and such- well I found that there was a big gouge in the drum and pads. so I think he might have switched the rear shoes with some old ones when he changed the front pads. well about 2 months of me telling my in-law to get the Drums and shoes so I can replace them he decided to get them. but not till after the ABS and BRAKe lights came on, and now they are on all them time.

well here is the real problem, the rear brakes don't work at all, now. after replacing them, I wanted to adjust them and I found out that they expand liek they should when u hit the brakes. so I took the Brake line off the drum and had my g/f push the brakes and nothing there fluid in the lines but it's not doign anything not leaking out when d/c'd nothing when she hits the brakes it should spill out but nothing..
and the ABS and BRAKE lights are both on. what could cause this?
WHAT COULD BE THE PROBLEM?

The check engine light is on as well and I had Autozone Scan it and the Engine is running Lean. what are some possible problems that would cause this. I have already tried to clean the O2 Sensors with no succes.
I know the Plugs could Posibly be fouled really bad and this could be the problem, the car has 138000 miles on it and I am sure they have never been changed. I want to get some info b4 I go ahead and change the O2 sensor(s) and or plugs and wires.