I don't think it would be so hard to add a female MC, as a bit of dialog changes and the intimate images could be with a strap-on instead.. But I don't know how long it would take to render the images differently..
The female MC could be of the tomboy variant as to not impact the story..
And for the Lesbian comments from the girls, they would still fit, if the female MC is a tomboy, as they are not into the girly girl type themselves..