I think it depends on your position. If you're the creator, then your headcanon = word of god and essentially canon. But if you only work on the show, your headcanon needs to be okayed and actually made canon in order to become so. But the crew have more inside info and insight into the characters, and more ability to influence canon, so their interpretations and opinions kinda weigh more.
But honestly I doubt they'll want to make all 5 of the main-ish girls blatantly canon straight, considering the amount of progressives in the crew and the fandom. Star, Jackie, Kelly are/ have been in straight relationships, Ponyhead actively dates dudes, but Janna is ambiguous and single and kinda butch. I wouldn't be surprised if they keep her single just to leave room for all the queer representation speculation