Is building a house feasible with this equity and net income?

Can you provide the full 70K€ or will kitchen, moving costs, furniture, and the cash reserve still be deducted?

The money for the kitchen still needs to be deducted. I roughly estimate about 15k euros. The rest can be used. Money for the move and a small reserve is available.

So, around 55k€ equity minus ancillary costs of 30-40k leaves about 20k€. So it will be about 95% financing. Not particularly great for the interest rate, but also not dramatic given the income.

Why do so many people actually believe that? With 3/5 you will most likely have to pay additional taxes...4/4 with factor is the safest option!

It depends on how the income is divided between the two partners. Tax class 3/5 is worthwhile when one of the partners earns at least 2/3 of the total income. I would say that's the case here. But in the end, the same result comes out with the income tax return anyway. However, 1350 euros of parental allowance will probably not be reached with the current net income of 1900. More like 1200.

But it will be because next year she will be in tax class 3 to increase the parental allowance ;)

Otherwise, thanks again to everyone for the answers!

Then that can of course be correct, that's how we did it too (:
Just remember to also switch in time. The tax class 3 must have been in place for at least 6 of the 12 months before the month in which the maternity protection starts.