BoV isnt too hard, all you need to do is pull it apart and clean it. There isnt too much to them. I wonder if a bit of upper engine cleaner wouldnt go astray either.
As for the air filter it depends what you are running atm as to how hard it is to change. AFM will most likley not be the cause if you just replaced it providing it is secured properly and is out of reach of oil filters. Fuel pump, fuel lines,
ecu and throtts most likley have to be diagnosed by a workshop id say.