As I posted in Rocco linked to Michael thread:
Godfather movies are not documentaries not factual They are for entertainment Technicalities not intended, in fictional stories
It is nice to know, fun to flesh out but not critical for the audience to be knowledgeable about the legal details, to enjoy the movies

Once He chose to reveal Pentangeli the perjury trap was no longer a trap because Corleones could identify and counter that person

Again nobody could uncover Michael's hidden interests not even the FBI Nobody could nail him because his web of fronting was like fort Knox

How did Geary penetrate Fort Knox?

I don't disagree the senate committee's strategy for Michael's perjury trap was “giving Michael the opportunity to tell easy lies under oath” Are you?! You deny this?! Is it true?! ie: enough rope to hang himself

The committee was obviously banking on their surprise star witness who has had no buffer between Michael and himself, corroborating the committee's nefarious charges [murder, crime empire, control of all the gambling and a lot more!] against Michael - It's up to five counts of perjury

However all the perjury trap ended up pointless with the committee's star witness not contradicting Michael and the sworn affidavit not worth the paper it was sworn on - All because the chairman was goaded into “the dumbest move in the all of GF2” telling Michael of their additional witness

We know how incredibly clever and resourceful Roth was - Lethal!

If Roth couldn't uncover Michael's “hidden interests, links, undeclared ownership and control in casinos” the chances of “the Commission's investigative staff uncovering Michael's hidden interests” is Buckleys and none!

Geary said Michael "owned or controlled three hotels" seemingly speculation due to their licence dealings but I doubt any direct links to Michael was uncovered

If Geary had uncovered the slightest whiff Geary would have squeezed Michael back with exposure or at least threatening Michael with an investigation for “Michael squeezing him via the hooker murder”

Everybody undoubtedly knew who Michael really was that Michael came to Nevada masquerading as 'legitimate' decent businessman - in his oily hair, dressed up in those silk suits - for 'legitimate' gambling business after consolidating his nefarious power in New York
However proof is scarcer than hen's teeth!

He didn't He couldn't

This is one of the occasions where the novel and film differ, in my opinion. In Part II, we see Genco almost literally wet himself when Fanucci gives him the eye. Vito, of course, saw through him immediately. So much so that he risks incurring his wrath by offering him much less than he demanded from the clothing heist. Of course there was no wrath because Fanucci was all facade. So would the movie's Genco have smelled a rat? Doubtful, given what we were shown of his judgement?

As you said, the novel and the movie differ. Genco's cowardice toward Fanucci was an invention of GFII. The statement about Genco smelling a rat was strictly from the novel. What makes it convincing for me is that Tom had two strikes against him as consigliere. First, he wasn't Sicilian, second, he was a lawyer. As a non-Sicilian he didn't fully grasp the irrational (to him) Sicilian need for vengeance despite the overarching risks--which is what Carlo did. As a lawyer, Tom looked to reconcile differences and avoid trials (or shooting in Mob affairs), when what was needed was violence to combat violence. The telling phrase in the novel came after Michael agreed to kill Sol and Mac. If I recall correctly, Puzo wrote: "Hagen looked glum - the statesman forced to go to war. 'At least we know what we're going to do.'."

Pop had Genco -- look what I got