In honor of the new season, this is my take on their status:
Yuri or Yuri crush:
Director - Lesbian or bisexual, sexually attracted to all or most of the girls that work under her. Yuri crush on Umiko, mainly because she likes hard-to-get girls and tomboys, and is acting like Umiko is some manga tsundere. Shizuku Hazuki.
Rin - Lesbian, in love with Yagami Kou, period. Fed up with Kou, but it's her fault for not confessing. Has noticed Aoba's crush on Kou.
Hifumi - Lesbian or bisexual, with an obvious yuri crush on Aoba.
Subtext, Probable, or Subtext-crush
Kou - Probable L or B, but too workaholic to care. Is not discouraging Rin and is not helping her confess. Likes Aoba's attention (practically worship, frankly). Is clearly not ready for a committed full-time relationship and that's probably why she doesn't make herself aware of Rin's full feelings. Realizes she's beautiful and is not ashamed of showing her body at all. Rin scolds her out of modesty, but Kou realizes there's a component of possessiveness too.
Nene - Probable L or B, subtext-crush on Umiko. Has a romantic two-girl friendship with Aoba.
Aoba - Probable L or B. Subtext crush on Kou. Romantic two-girl friendship with Nene. Is not discouraging Hifumi.
Umiko - Very inhibited, aware of Nene's subtext crush on her, not discouraging it, nor trying to channel it into mentor/mentee sempai/kouhai or work friend or even friend direction - just letting it develop. Very aware of Director's constant desire to sleep with her, and she discourages it actively. Director treats it as playing hard to get and assumes if she's patient, some day (maybe after a drinking party) Umiko will give it up.
Not at the level of subtext:
Hajime - Not very sexual, either straight, bi or lesbian. The other girls all notice her enormous breasts, given she jumps around and waves them all the time. Probably innocent to most or all of the subtext and yuri around her.
Yun - A lot more aware, and since she keeps to herself she may have a subtext interest in Hajime covered up by bickering, and jealousy over Hajime's body. She also might be interested in Hifumi or Aoba. But she does keep everything to herself. You have to infer it from things she says sometimes and the way she says them.
Wako and Momoki: no idea.
https://s-media-cache-ak0.pinimg.com/564x/27/1b/f9/271bf92a3cd1f1105de8bd60dc5404cf.jpg
Hotaru (lower left) and Chinatsu (upper left): Possible crush at least from student to teacher, if not both ways.