1st story: Haruhi, 2nd: I am not sure, Mikuru? 3rd: Tsuruya. 4th: Yuki Nagato, 5th: Tsuruya again? I am not sure if male characters are generic or named, they are not drawn too well.
No, the fifth story features Ryoko Asakura and Itsuki Koizumi. Kyon is the male appearing in the first four stories. And yes, Mikuru is the girl in the second story.