Thanks Turnbull

“Tom probably would have thought that his brother, Fredo, needed him more than ever--certainly more than Michael did”
Spot on! I had forgotten about brother Fredo and Tom's family loyalty

A side question please, how would Tom react / handle the situation if Tom somehow found out Fredo's role in Michael's [and Kay's] murder? Even the children if they had come to play with their toys

Whilst “Pentangeli had a loud argument with Michael in the boathouse, witnessed by Tom and Neri” Pentangeli's parting words were,
“You'll have to excuse me -- I'm tired, and I'm a little drunk! And I want everyone here to know -- there's not gonna be no trouble from me!”

I can appreciate! how scared anyone would be if Michael Corleone, showed up at their home, unannounced, especially after Michael's murder attempt, then absolutely be relieved when they realise it is not them Michael is after

Though I still can't see how “Pentangeli would have made the perfect patsy for the Tahoe shooting”
Perhaps initially but the logistics of arranging the Tahoe shooting, in such a tight time frame, seems far fetched

You are right! Neri and Rocco bloodshed was more likely
Neri and Rocco were too much in competition with each other and whilst I believe Neri was the smarter of the two, I don't think Neri had his own men like Rocco

As you say, Turnbull, Roth, clever fellow, played Tahoe and Havana beautifully

Vulture is a patient bird indeed
“All Roth would have to do would be to sit back and let them fight each other then pick up the Corleone casino holdings after all the bloodshed