...his retirement and turning things completely over was a convenient way of implementing his plan and removing himself at the same time...
Well, of course it was. I doubt anybody is saying it wasn't.
His goal after Sonny's death was to end the war, and get Michael home. At the meeting, he swore on the souls of his grandchildren that he would not be the one to break the peace.
And he kept his word.
Never did he say though, that he would not have a hand in planning what might occur after his own death.
...I don’t think that Vito not being alive when the hits took place completely gives him a free pass.
Actually, yes it does. (If 'free pass' is even what you can call it). Since he wasn't alive when the peace was broken, he did not break his promise.
... Whether or not you think he broke his promise, you must admit that he came awfufully close.
Can you explain how.