Can anyone link me a sort of "official" confirmation that Goji is going to be an indestructible force of nature?

You don't need a link to confirm such a thing, what it means by indestructible is that he can't really be killed like his 1954 counterpart.

@Shazothehedghog, Well, that all depends on what series your connecting it back to....in the Heisei series they talk about this Godzilla as though he is the old Godzilla becuase they claimed that a corpse was never recovered.  In the Millennium Series, however, that Godzilla was killed, by the Oxygen Destroyer.  Then they recovered the bones years later and used them as the frame for Mechagodzilla so they could kill the current Godzilla.

Yes, I do need a link to "confirm such a thing". I'm not someone who just blindly accepts things that people tell me. Which is why I'm considered a major A--hole by most people.

Director of the Shawshank Redemption Frank Darabont is a huge Godzilla and Kaiju movie fan (he actually had a cameo as one of the biplane pilots in Peter Jackson's King Kong) and he was asked to come aboard and do a rewrite to the script.  He did an interview which I have provided the link to below.  It quotes him in the second paragraph about him writing Godzilla as a "terrifying force of nature" as opposed to a "mascot."  Darabont's rewrite was the last of te rewrites to be done to the script.

Frank Darabont's Rewrite to Godzilla

If I remember though, Darabont was pretty much kept in the dark about story and plot. Again, if I am remembering correctly, they only brought Darabont to clean up the human interaction and dialogue.