[Potential Spoiler Commentary] We don’t believe including characters who are not straight/cis would have deeply affected Akito’s decisions regarding the Zodiac or any major parts of the overall story.
While men and women being unable to hug is a symbol of not being able to connect with “outside” people, the story is so much more than than the simple act of not being able to hug. At most, this is a (heteronormative) side effect of the curse. The curse is not the hug-transformation; it is the bond between the Zodiac members and god. (And the fact that this hugging problem is specific to men/women is a heteronormative standard frequently found in the media today.) After the first few volumes, we rarely see the Sohmas transform into their respective animals. Also, there is definitely more that can cause the transformation, other than the act of hugging. The bonds are strained not only by romantic love, but outside forces and creating new bonds to friends, goals, and dreams, as well. The series surrounds the characters finding themselves, not necessarily the straight, romantic pairings that lead to hugs.
It is true that Akito has an intense hatred of women. But there is so much more going on in Akito’s mind (and the rest of the story) than her being afraid people will find “true love.” She could still have this hatred, suspicion, and jealousy toward women while another character was gay, bisexual, pansexual, etc. The bonds are already weakening, and it is not just hetero romantic love that is causing this. Kureno, for example, was released from his curse seemingly at random. Akito is constantly worried about anything that could sever more of her bonds, which does include possible romantic love (with a woman other than her). But, again, she is already afraid of a lot more than that. In our opinion, she’s holding on as tight as she can while she waits to see what will come out of the deal she made with her mother.
Fans express their frustration that “true love” in Fruits Basket (and most media today) is almost exclusively defined as a man and woman. The fact is, a character could have been included who was canonically defined as not-straight/not-cis. The rest of the story would still have come into play. Akito would still have made a deal with Ren to see how some of her Zodiac would fare out in the world, believing that someone (not just a love interest) would reject them harshly and they would come crawling back. Kyo would still be fighting to beat Yuki and escape his fate. Tohru, Rin, and Shigure would still be fighting to free the family from the curse.
Fans can be frustrated that more diversity wasn’t included when there are ways it could have been worked in (instead of teased or hinted). We believe the effects of including more diversity in the characters wouldn’t have inherently changed too much about the original story or its central messages.
But because Fruits Basket is already published this way, we will never know how Takaya would have written the characters under slightly different circumstances! It’s all up to personal interpretation.
-C & J