41 can't be a KOEO code (can't test o2 sensor when the engine isn't running), so I'm going to assume it's really a continuous memory code. I'm also going to assume that it passed the KOEO test.
KOER 64 would be easily set if the test were performed on a cold engine. However, it's interesting that you didn't get the same code for the KOEO test, if this were the case. A guy would have to think through this carefully to see what would cause this code to show up in the KOER test, but not the KOEO test. One thing, not that codes don't always mean a bad sensor. Bad wiring is just as likely a cause.
KOER 74 is almost always operator error. Computer expects to see you press on the brake pedal after engine id is output. This is often neglected, resulting in the code.
You say you cleared the codes. It should be noted that KOER codes can't be "cleared" in this sense, because they represent hard faults present at the time the test is performed. They can only be "cleared" if the condition that caused the fault corrects itself/is corrected. KOEO and KOER codes are not stored in the computer's memory. CM codes are the codes that get "cleared"
Anyway, after all that, the only thing I see that would likely contribute to the gas smell is the cm 41. Are certain it hasn't come back? I would pull the codes again to asssure myself there really is a pass code in memory. I have seen CM codes show up without the CEL coming on. It's also interesting that you don't get a KOER 41, which indicates that the system operates "normally" (as far as the computer is concerned anyway) at least part of the time.
EVAP system (was mentioned) are you certain the CANP solenoid is opening? EVAP tubing clogged?
Any leaks in the fuel delivery system (filter, FPR, fuel injectors, tubing coming out of the tank)?