>>1276181HA!
Yomi was showing more concern for Mato because she was missing and also in distress in the Other World. Kagari and Yomi's "reunion" was offscreen, but you can bet your ass it happened soon after the Mato/Yomi midnight hugging session. And they had a lot of catching up to do.
Kagari/Yomi was the most and best developed of the many multi-directional pairings. And it really was a threesome end.
Anyway, even if you disagree with that, you're just stupid if you don't think there was significant material to support almost any pairing you want. I could spin the ending as Mato/Kagari and YomixForeveralone as easily as I could Mato/Yomi.