If I read this correctly, your financing is missing the kitchen, say 15,000 euros, and furniture and equipment to be purchased, which we will estimate at 10,000 euros. This would completely use up your equity capital without leaving any reserves for other things.
As long as both of you are working, this financing is reasonable in itself; I would only include the aforementioned items in the financing.
However, once only parental allowance for the second child comes in, relatively little remains. It would be sensible to have a reserve for 1-2 years that you could access if necessary.
And regarding the conditions: Our project is almost identical (395,000 financing with 40,000 equity), we get 2.15% for 15 years + KFW 124 and 153. Unfortunately, it has risen somewhat in recent weeks...