Livewire was an original character created for S:TAS by Timm and Dini. Later on during Justice League Unlimited Killer Frost was introduced to the Diniverse, and Timm did make her look very similar to Livewire (pic related).
But Killer Frost has been around since the 70s, she started as a Firestorm villain, there's been three completely different people who called themselves Killer Frost, and many different designs. In the 90s when Livewire was first appearing on TV, I think KF was basically an edgy 90s ice monster. Now we have nu52 Caitlin Snow who's getting a redemption arc in JLA, and it's hard to humanize a character who doesn't look human. I don't think Livewire's even shown up in comics since nu52 happened.