Bathroom planning: Combine guest bathroom with children's bathroom?

The point is that we are building a Town & Country Bungalow 131, and this is the chosen starting point. But nobody wants to accept this; instead, they want to convert me to their supposed happiness. So my ideas are weighed against their own ideas, whereas the actual comparison should be with the B131 type.

Let's take the current example with laundry sorting, please explain to me - to what extent the standard B131 floor plan is better suited here.

The crux of the matter is that we are building a Town & Country Bungalow 131,

You are not building with T+C, nor does T+C have any influence on this house. I also seem to remember that you even changed the length. Wow. T+C only exists in your imagination because you know the price from them or have asked about it for your construction estimate. You are afraid of losing control of the possible price if you deviate from the scheme. But whatever: rectangular might work too, and if that is your wish, that’s okay. But not even adjusting 20/50 cm or however much outward to make everything somehow standard is kind of silly, especially since the framework only exists in your head. There may well be space on the property...

please explain to me - in what way the standard of the B131 floor plan is better suited here.

Who says that the B131 from T+C is great? better suited? I would never build it. I would never have favored it or taken it as a reference floor plan. You are the one who brought it into play. Okay, to your question: the utility room in the 131 is easily accessible for everyone via a short route.

I just want to say something about your initial question. Keep the two bathrooms as they are marked in the first overall plan of your new contribution. Absolutely no laundry in the guest bathroom. I empty the 3 laundry baskets from the upper floor, for example on the floor, then sort into the laundry tubs. I don’t know how others do it. This is the method all my acquaintances also practice. That requires space and sometimes things will just be lying around, which guests definitely do not want to see or should not see. The children will probably also shower in the bathtub. So pay attention to a tub with a sufficiently flat standing area. There are special models for that.

The point is that we are building a Town & Country Bungalow 131, and this is the chosen starting point.

You are not doing that at all! You are neither building with Town & Country nor is it this bungalow, because you have already changed everything 100 times. Not even the exterior dimensions are correct. What does this design have to do with yours? Nothing!

But no one wants to accept this, instead they want to convert me to their supposed happiness.

Of course, otherwise you might as well just build the B131 as it is.

So my ideas are weighed against their own ideas,

No, we look at whether your needs are met by your designs. And yes, tiles also count points that you yourself might not have considered, but are essential for a functioning everyday life.

whereas the real comparison should be with type B131.

For what purpose only?

according to your statements, 80% of the builders of 'smaller' prefabricated houses would be completely unhappy...

It hardly gets more misunderstood. I just wrote that the happy builders are precisely those who do not want to keep banging their heads against the wall at the 90%-perfect point!
90% is already paradise according to Pareto. Apart from lowering your happiness index, you can no longer "gain" anything by continuing to nitpick.

The point is that we are building a Town & Country Bungalow 131,

No. First, it is not a Town & Country B131, but a completely different house than this former planning basis; second, only a fool would think that the price has anything in common with it; and third, you will N.E.V.E.R. build it, because you will have overperfected yourself to death beforehand.

To return from the off-topic discussion to the bathroom planning. Dryer & washing machine back in the utility room. The children's bathroom/guest WC remains a bathtub bathroom. Parents' bathroom only with a shower. Clear dimensions 4x3.70, door approx. 86, toilet island arranged asymmetrically.