The fact that Morgana said something about him describing Merlin in pictures made him pretty sure that they probably knew two different Merlins, which was strange but not impossible. He'd never been all that clear on things like if Snow White and Cinderella had married two different men named Prince Charming or they both married the same one, after all.
Riku pursed his lips a bit, thinking about the options when it came to letting someone touch his keyblade. But after a quick moment he shrugged and held it out to her. After all, it wasn't like she would be able to run off with it or anything, the odds were in his favor that she wouldn't be able to handle it for more than just a few seconds before it teleported right back into his own hand. "Yeah, sure." And even if she was one of the very few that would be able to hold it for longer than a matter of seconds, Riku was sure that he would be able to get it back without even blinking.