Different universes. I can't remember what the in-game explanation is for there being two Killer Frosts, but the KF you capture is the DCAU version, the one at the Gotham event is the Assault on Arkham version (IINM).
Easiest answer is that there's been multiple Killer Frosts for quite some time. Even in the confines of the DCAU the Killer Frost we're accustomed to seeing is technically Killer Frost 2. Killer Frost 1 in the DCAU never actually appears in a TV show as far as I'm aware and only makes an appearance in a comic set in the DCAU but she did apparently hold the name at an earlier point in history than the one we know did. Outside of the DCAU there's typically three potential names for Killer Frost: Crystal Frost, Caitlyn Snow, and Louise Lincoln. Unfortuntely due to only appearing as a secondary character in Justice League Unlimited we don't have a name for the DCAU Killer Frost, however we can likely assume that she's Caitlyn Snow as the one from Assault on Arkham is Louise Lincoln. In part because the one from the DCAU comics has design similarities to the Crystal Frost version of the character and in part because Caitlyn Snow tends to have a more punkish design.
The Justice League show was made 10 years before the creation of Caitlin Snow. Dora Smithy (Mr. Freeze's sister-in-law) is probably DCAU Killer Frost (but not confirmed).
You don't "get" her like you can get Killer Frost 1, she only shows up in the Gotham event where she has several scenes
Yeaaah, that's not actually canon to the DCAU and that so called sister in law of Freeze does not actually resemble the Killer Frost of the DCAU. Face, skin, hair colour, and eyes are all wrong. Technically speaking the comic I mentioned isn't canon either but it doesn't contradict anything. Regardless the Killer Frost of the DCAU is never given a name and the only assumptions we can make is that it's one of the three possible names. If it's not Caitlin Snow then it's probably Crystal Frost. But ultimately it doesn't really matter since the DCAU Killer Frost is nameless and therefore could be anyone. For all we know her name could be Elsa Fostleberries.
I hate that all the bodies are practically just copy-pasted with some recolors here and there, the art is pretty damn good. probably the closest thing to actual DC looks, at least face-wise. but the same body types and nips just ruins it and just seems lazy. I shudder to think how long it would take if he gave each girl unique nips,vags and breast shapes.
Well... that's kinda lazy if you ask me. Here's hoping they will expand on it, or - if we can get two of them on the same party - there will be some hint through character interaction.
it's cause batman knocked lex out
