I believe Michael “pleading the Fifth” was never an option even if Michael had known about “Pentangeli's survival” before “Michael testified”

Michael & Hagen towards the end of 1
Originally Posted by Lana
  • What would Michael have done differently? though Nothing!
Michael in reality could never have taken the fifth amendment to the US Constitution

So Michael would still have lied under oath, denied all the charges and committed perjury
ie: It's up to five counts of perjury rap remains unchanged

Michael wanted to show that he has nothing to hide, nothing that would incriminate him
So Michael taking the fifth was never an option

It occurred to me, seems far-fetched....
Michael locates / contacts Vincenzo out of the blue and Vincenzo comes all the way from Sicily to help Michael against Vincenzo's own brother Frankie because Omertà is more important than his own brother's life?

My take is there was never any danger of “Frankie's family would be killed” same as Vincenzo

As Tom said
Quote
Frankie, when a plot against the Emperor failed -- the planners were always given a chance to let their families keep their fortunes
ie: “financial support” if the planners killed themselves

As far as Michael is concerned nobody gets a pass Everybody who plotted against Michael must die whether Frankie the good old man who was loyal to Michael's father for years or Fredo, Michael's own 'weak and stupid' brother

“Pentangeli was stuck between the proverbial rock and hard place” indeed
I had forgotten the NYPD and Frankie's "possession, Murder One.." and a lot more!