Might as well answer these the best I can...
My understanding is that the AAV is simply $300m/11, & if he accepts the option, his AAV will be $1m for that year (although I assume that will be below the league minimum & they'd at least have to pay him league minimum?)
I believe for AAV this is a $150m/3 ($50m), and if he does not opt out, the next 5 years are a $70m/5 AAV ($14m).
If the player retires, that would only impact the consideration of any signing bonus I believe. If the player retires, they stop receiving their salary & as such there's no future AAV issues related to that salary they are not receiving. The player is obviously heavily incentivized not to retire, even if they are no longer a competent baseball player.