City villa floor plan 180m², basement, 3 children - Your opinions on this?

A [Satteldasch] does not have to be isosceles, that could help.

However, we have not yet seen a house with 2 full stories that was lower with a gable roof than one with a hip/pyramid roof. What are common city villa roofs? A hip roof? We could also imagine that, we are not necessarily bound to a specific roof shape as long as 2 full stories are maintained.

The affordable city villas have a pyramid roof, which falls under the hip roof category. It then has no knee wall and cannot be converted due to the wooden construction, at most as a crawl roof for storage.
What you are planning is a more expensive category: You are planning a) a beam structure that can be converted and walked on, b) an additional knee wall, c) another staircase d) a ceiling that has to carry significantly more than intended for storage space, e) insulation that turns a cold roof into a warm roof, f) a livable expansion g) some technology like heating, h) a nice window instead of a roof hatch i) higher scaffolding during construction and k) exterior wall material. And that, although you already want to build with an expensive basement.

Apparently our floor plan isn't all that wrong,

I took a look: 2 users who do not exactly stand out with counterexamples and alternative approaches in other floor plan discussions.

1) Both kids’ rooms each give up one square meter of living space, and 2.60 (and not the specified 3.50) room width is not something that can’t be improved.
2) The bathroom has the shape of a storage room.
3) Pantry is a waste of space.
These are obvious points, no need to go into every detail here. I could complain more, but setting that aside: the general contractor’s planner will draw this up for you 1:1. He will not advise, recommend, or improve anything “what the customer wants, they get.”
The problem is: you see and plan this as a layperson, are fascinated by the 3D button, and no longer consider the demands of a trained architect for house construction because everything seems so easy. At least let the planner do their job and loosen the 10x10 grid, which here only serves as a bad corset without this being shown here.

active support

Does the active support also have time on the days you need to get started? The support for the theoretically targeted days must still earn their own livelihood... or are these people unemployed?

But it surely won’t be a piece of cake,

I can well believe that. If my husband should still work elsewhere on the weekend, he is on a short vacation with me by the third weekend :p That may sound stupid, but that is the reality – you can’t keep someone on a construction site for more than one weekend. Not for free either. With good friends and relatives, it might work for a week. But no one gives up their annual vacation. In that respect, I don’t see the 45,000 equity for the shell.

I have seen the issue of personal contribution work very well in 3 cases within my circle of friends, each in different constellations. Every weekend and many evenings were invested with a clear goal. With a lot of help from the circle of family and friends. That life sometimes comes to a standstill in between is part of it, but in all cases the respective partners went through it together very well.

I have seen the self-help approach work very well in three cases within my circle of friends, each with different constellations. Every weekend and many evenings were invested with a clear goal. With a lot of help from family and friends.
That life sometimes comes to a standstill in between is part of it, but in all cases the respective partners got through it very well together.

Yes, it can work out well. But we have indeed often read here that it turned into a small disaster – with additional financing because it was about the painting work including plastering... I don’t remember exactly.
I was able to witness in real life how a football team along with their craftsmen built a house. But that was several years ago... team dynamics make a lot possible.
But to build extra large, to fill the missing equity with external manual labor mortgage that you are dependent on, I consider that unreasonable. The good thing about the project is that the OP, that is you , can find out pretty early whether it works. Then the helpers are still enthusiastic.

Nevertheless, one must consider that the helpers have to go about their actual work during the day. So as the builder you are mostly on your own. Many people suppress this fact.

Apparently our floor plan isn’t that bad after all, since the criticism mainly targets the budget and the own work :) Or are we interpreting this wrong?

I’m afraid you are. If the entire project is calculated unrealistically, it’s not worth discussing the floor plan. And to add something to that: I like some points (e.g. the living/dining area), others (e.g. the bathroom) are rather scary to unusable. And as soon as you start to fix things in one place, the (house of) cards collapses somewhere else. Not that 100 m² of floor space is small, especially not plus basement and attic, but with the room program that’s rather not enough. And things like storage space aren’t even taken into account yet.

Pantry is too narrow. With a 15 cm shelf, extremely expensive storage space. Add one more cupboard to the kitchen.
And the freezer?
I find the cloakroom small for 5. Especially since every time you have to go through the dirty area and climb over shoes to get to the toilet.
The bathroom upstairs is an absolute no-go and will be buried with the changed staircase.

If the floor plan is oriented to the north, parents with child 3 swap.