No, please, anything but that! I've given my 2 cents on the matter before, but that this game doesn't have the cancer that is the "what is your relationship to those characters" system works in its favor.
Putting in placeholders that will need to be replaced by the user input later on just limits the writers' creativity and creates weird sounding sentences that break the immersion. The relationship the protagonist has to Jo and Flora is perfectly clear by their interactions and dialogues, which feel perfectly natural. I'd rather we have that than horrible writing and a "Wow, she's so hot! What am I saying, she is my mother!" and "Me and Flora, my sister, have always had a bit of a rivalry going on." to show that the characters are related.