Those are both valid interpretations.

I'm really just playing devil's advocate here, largely because I expect the WT's card to be errata'ed; in the vein of Devil's Advocate, however, the AE example breaks down since it stipulates the exact set symbol and number of the character to be replaced, while the Wonder Twins' power does not have any such disambiguation.

For instance compare the Bruce Wayne AE power:
to the WoS Spider-Man Web power:
and finally compare it to the Bucket of Water portion of the Wonder Twins Trait:
The text for Bucket of Water is more similar to the Web Tokens than it is to the AE mechanic. Furthermore, the Web Tokens were also 3D objects whose description happened to be listed on the characters' cards, much like the bucket of water.

It was stated in a press release that a "SPECIAL" token could be proxied for the Web Tokens, which sets a precedent. While nothing has been said about the Bucket of Water directly, if I am allowed to proxy a standard "special" token for a Web Token what's to stop me from proxying a standard light object for a Bucket of Water light object?

Again, I expect there will be (web)errata to the description on the Wonder Twins' card, but until then a case can be made.

EDIT: I see Harpua's weighed in. I still maintain the necessity of errata, but don't disagree with the ruling.

Web tokens are in absolutely no way objects. They are 100% terrain.

I don't disagree that errata for consistency would be nice, but not having it would not change anything, imo.

Er... yeah, that was really a mistype on my part. I meant '3D element,' but typed '3D object' without really meaning to use game terms. My bad.

Works for me.

By way of absolute crystal clarification, though, this does mean that the only way to use the Bucket of Water portion of the Wonder Twins trait is if you actually possess the LE object, correct? No PnP proxy, or anything like that, yeah?

That is correct for official play, such as at GenCon. For local organized play, it can't hurt to check with your judge.

Now, if you're playing among your friends and they don't let you proxy, may I suggest finding new friends?

That's a rather harsh solution to a problem that can be solved with some beers
Always worked for me ! (bring some tequila, in case beers won't do the trick).

Fixed it for ya

I would use an Oreo to proxy the Bucket Of Water. Just to piss them off. Then I would eat it.

Lol, I ask because I am the local judge.