Yes, there will be more characters in the future. (we've just been stuck on the reworks for over a year but we're nearly done with that). As for the building on the left side, this is like the dormitory for the characters so we're not planning on expanding it.
For the barn yes, it will be expanded when there are more characters (currently you can barely fill all the working slots so it's not worth adding more just yet). The pleasure room will also be expanded to have about 4 more worker slots. As for the plant, they should have both 3 animations they can randomly pick from. (they do share the same animations though)