That was my take early on in the series when they did the same thing with Grace's partner (used gender-neutral pronouns). I thought THAT would have been the most interesting person to make bisexual (or a closeted lesbian). Imagine finally being in a relationship with a woman when your husband turns out to not be dead?
But in any event, yeah, whenever a show uses gender-neutral pronouns to describe a character that we don't see, I assume they're trying to hide that a character is gay (or, in the case of the current show, All Rise, which played the pronoun game in their pilot with their main character, I assume they're keeping their options open - that could have been the case here, too, honestly)
By the way, speaking of Grace's boyfriend, Danny, what if Danny is ALSO a survivor, but from a different event, like Zeke? And so that's why Grace's baby has callings. Duh duh duhhhhhhhh!