I don't know how many meetings Marshall had with Goodell. It was my understanding that he meets with players after every unfavorable incident, much like he did with Marshawn last year, where there was no arrest involved and just a traffic ticket. And even if he didn't meet with Marshall after his first arrest, he should have met with him after his second, and then suspended him. From Goodell's own words, players should themselves know that they're held to a higher standard and don't need him to remind them of that fact.
So again, I can see Lynch getting a game and it being reduced to a hefty fine, after the NFLPA argues the above. Everyone can have their suspicions on his state of impairment last year, or whether he was partaking in some reefer, but there were no charges related to those, and ultimately he was caught for a gun in his trunk that wasn't harming anyone. And those are as bad as, or worse than, what Marshall did? No way.