"You sound like you want to do the right thing. We want to do the right thing. I think if you were a horrible person you probably would've zapped me by now." She said motioning to the bottles. "I'm willing to give you the benefit of a doubt." That addressed the first part of his concern. Kate wasn't going to expect him to completely trust her. She'd just hopped over a few rooftops, said hello and extended an invitation. It was mostly inspired by his long spiel. This could have easily been a set-up. She preferred to be more optimistic, but she'd keep it in mind regardless.
As for the second issue, "I can get you a costume." The smile that she gave him was one that told him not to worry. "It helps people not identify you when you're not fighting crime, and that helps to protect your family." At least, that's what she reasoned out. In her case, it was to keep her dad from figuring out what she did.
Pulling out a tiny notepad, she took a pen and scribbled down the same address she gave Teddy. "You can tell me if you've got any ideas on what you'd like on Wednesday night at this address," she said handing him the paper. "That's when we'll all be meeting. You can bring a generic mask around that time if you'd like."