Alternate to Avalon
Reference made above to "tracking coastal within glide distance of land" to Essendon.
Newsflash. Port Phillip Bay is an almost entirely enclosed body of water and one can "track coastal" in either direction. A route over the heads via Port Arlington and Point Henry leaves a tiny over water segment, and is shorter than tracking to Essendon. In fact, distance is not a factor if your aircraft is in good shape, the engine is turning and burning and you have fuel in the tanks.
In dismissing Avalon as an option someone referred to the perils of taking a direct track as it was "over deep water". Deep water only becomes an issue if you are concerned about losing control and spearing in. Hellooo! If that is a concern, under no circumstances should you choose a destination which requires flight over built-up areas. To be brutal, if the aircraft was at risk of catastrophic failure, the deep water only becomes an issue for recovery of bodies.
As for comparison with US Air 1549 (Sullenberger)?
That is the reddest of red herrings. Sullenberger's choice of alternates was limited by having 0/2 engines running and sfa altitude. He, in fact, chose the option of ditching in the Hudson for the very reason that an attempted approach to Teteboro could have put lives on the ground at risk.
The S211 had wing damage but it seems there were no issues with fuel or engine function, so choice of airport on those grounds was not a factor.
There seems to be a level of emotional reaction here in supporting those involved.
Understandable, perhaps.
But that, plus $5, will get you a cup of coffee.