Hello buddy!
Now multi-tits will be a rarity. Martha and Stacy have them because that's how they were designed. But sometimes you can meet similar characters (the game is quite large). The game already has and will have a little more items, etc. which, if handled properly, will be able to add/remove, change, etc. different aspects of appearance (difficult to explain). It’s just that at the moment the ingredients and some things are not involved in the game, although they can already be found and obtained. This all applies to the next updates, where we will partially or completely move away from the linear plot, giving the player freedom of action.
Kaise, Greta and other similar characters in the world of the game are anthropomorphs and some of them will actually be able to take on the image of the creature they resemble (for example, Kaise can really turn into a fox). But no sexual content, etc. It won’t happen with them like this.
The transformation is quite varied and included in the plot.
As far as I remember, NPCs only have a sympathy panel for the main character.