Definitely Ayato for me! And yes, they would go along very well; despite appearance Ayaka has a strong personality (Ayato's about Yoimiya line) and will able to handle Itto's eccentricity. Itto also have a high respect of Ayaka, and also introduce her beetle fight and TCG, which Ayaka find it a breathe of fresh air... Not to mention Ayaka will also notice how Ayato "change" when Otto's presence... She will approve their relationship easily, be it friends or as lovers! 😊