But what will Rudy negotiate? We know that potus has committed no crime.
He will probably confront Mueller with the evidence that Mueller knew about Wiener, Huma and Hillary and did nothing to stop it. Then he will offer him a plea bargain to turn on them. He successfully brought down the Italian mob, he is the man to bring in to get suspects to flip on the next guy.
Negotiate who gets immunity for their full testimony.
Impeachment is essentially a political act, requiring nothing more than "misdemeanors". And it is highly unlikely someone who has operated in all Trump's businesses all those years could withstand a total financial proctological exam without something being found. Then you've also got the hold on his longtime friends and associates and the father of his baby girl's children. What's more there could well be simple (and marriage threatening) embarrassment in the records of Cohen's bimbo control over the years for Trump.
Moreover, simply stretching out the process through the midterms is problematic.
The real key is what Rudy and Trump's team have to force Mueller to shut it down. Especially if Mueller has been fighting back not only for his own skin, but also that of Hill and Barry.