Confused

I recently inherited from my dad that he was in the process of fixing. I have a list of everything he replaced. The car was running great for a few weeks now with the issue of the check engine light being on. The code is for the O2 sensor bank 1 which he replaced. All of them actually. It is also throwing a code for an evaporator system leak. The car has a brand new exhaust on it as well. I tried resetting it and clearing out the codes a few times now. Today when I got in the car and started it the speedometer went the whole way up to 70 even though the car was in park. It would not go into reverse. The ABS and Brake lights were on as well. Like I said he replaced all of the O2 sensors, but I cannot get the light to stay off and he also replaced the Transmission sensors. Among other maintenance that should get done. I have no clue what the problem is. My dad was a mechanic 50+ years since this is the last car he worked on I really want to fix this problem so I can keep the car. Please help.