Cora and Thomas
Thomas didn't know Cora well, but he knew that she was from Lydia's world. They'd spoken a couple of times on the network when she'd mistaken him for Stiles, but they didn't really know each other. He didn't see any reason not to change that.
He'd been here long enough to understand a bit better what exactly Halloween was, so he was actually wearing a costume. It was a bit generic, like Lydia's, but at least it was a costume. He was dressed as a football player - something he'd never gotten to be but probably would have been good at.
He grinned at Cora warmly as he approached, holding out a hand.
"Hey, I'm Thomas. You're from Lydia's world, right?"