that would require a lot of extra work so I have no plans for it
Sorry for my blatant aassumption on how you've coded your game but couldn't you just make some kind of script that runs when the player clicks a button for she/her or they/them pronouns that effectively just scans for every use of "he, him, his, he's" and switch them with the appropriate pronoun choice? Obviously you'd need to be case sensitive but from my understanding it doesn't seem like "a lot of extra work."
Nah, it's not that simple, every line is hardcoded in, even changing the timings requires me to go line per line, here I'd need to replace the pronouns each time with variables on a project with thousands of lines of dialog. Can't do an automatic thing either because sometimes the girls might say "he" and not refer to the player. Also would need to figure out if it needs to replace "his" for "hers" and so on or lowercase/uppercase like you said yada yada. Sure, a skilled coder would pull it off in a flash but my bird artist brain can't.
That's from a technical perspective, but since I have the chance to point this out now I'd say that Anon is canonically a he. Has been referred to as such in my comics from the start and I want to keep it that way.