That's probably exactly the way that it happened.
I edit emails every day at work... usually when I am passing information along to a vendor where I don't want to add the part where the sales rep screamed about why the vendor wasn't performing on time.
He probably plead guilty because the last thing he wanted was to go through the legal expense of years of trial when there was no jail time involved. He even got his law license back after a year. Seems like a win-win for him.
Uh, first, there were a bunch of convictions in the Russian Collusion case, which is why Trump had to hand out a bunch of pardons on his way out the door.
He even considered pardoning himself, until someone explained to him that accepting a pardon from himself would be an admission of guilt.
Second, they TRIED to charge the Hillary campaign, when they put Sussman on Trial. The jury found him not guilty. They saw a bullshit trial when they did so.
So all Durham is left with is someone who changed an email in good faith and admitted he made a mistake.
Third, Russian Collusion is something you WANT to investigate! Holy shit, man, if the Russians can change the results of our elections, that's kind of a big deal.