So I'm not sure which you mean, the planned character being transformed into a futa, or if MC should get a futa transformation.
Between the two options, I'd rather do the latter of the two. Having a planned character be transformed means I'd have to do 2x renders of every time that character's genitalia were visible, which then if any of the other girls were involved in any way, that'd then be up to 8 scenes per scene. Char 1fem|Char 1Futa multiplied by expansion events. (2x2/2x3/2x4)
Things multiply VERY quickly lol.
The reason I'd be willing/prefer to do the latter, is that MC is rarely visible to the player. So it'd mostly be a symbolic change that would only ever come up in the rare scenario MC looks down (shots I tend to avoid due to DazStudio Jank) or any time they are in a photo/mirror. So the additional work load would be insignificant. This specific thing was actually previously talked about in my Discord with having the option for the player to turn MC into a femboy/trans optionally. It's something I'm still heavily considering doing, but it will take some time until the story is ready for something like that.