Probably achieved by hacking into the game files. Hypothetically you can hack into the files (illegally) and get characters you do not own.
I dunno for a fact if the files for a given character are in their stand or the game itself. If they are in the game then it can be hacked. if they aren’t then I dunno.
Or, look at the date the vid was posted.
Brickset listed the 2 character which I found odd but now I have more confident of their legitimacy.
Edit:
It’s legit
That says that the character exists in some form but it does not confirm the data used by the person to create the video was legitimately obtained.
The video maker never showed off the figures or did anything to prove they actually got the product in hand.
Hey guys, just found this on ebay while searching for LEGO Dimensions news. Seems legit. Also the number is the same as on brickset.
Edit: And…they’re sold out 
Yeah I did some research.
Apparently ones with the trans gold base are special ones for “special” people.
“special” as in “I will never get these and never complete my collection” or just “hard to obtain, but possible/expensive”?
Huh, so now there are gonna be promotional characters
It looks like they all belong in this category.
Although I could be wrong.
Their Officially teasing the next wave, the major announcement start June 9.
Seems like they already started teasing the new franchises!
This sounds suspiciously like someone who cannot be named:
https://twitter.com/LEGODimensions/status/740234042461671424?s=09
EDIT: copying the link didn’t really work as planned, just click on “LEGO Dimensions”
Well someone manage to leak the image early… Some of the figures look wierd tbh, mainly AT.
I got bored of Dimensions a while back, and sold most of them. I want the AT set to come out though.
New Themes confirmed:
Adventure Time
The A-Team
Mission: Impossible
Teen Titans GO
Sonic The Hedgehog
Fem Ghostbusters
Harry Potter and Fantastic Beasts
Gremlins
E.T.
The Goonies Sloth
I mean
the movie ones make sense
but
Sanic and TTG?
my god…
AT seems alright but a bit odd though
oh well I guess more CN cartoons right?
Yeah, where is Mario and Raven?
Also Samurai Jack where?
Got2gofast in Lego Dimensions… right?
I honestly didn’t believe they would add Sonic.
I did, but I also believed they would add Mario with Sonic or before him.
Oh, and Mission Impossible- that was unexpected too.
I cannot express how excited I am for Sonic. He’s cool.
