Inheritance property - payout to siblings, then construction - financing?

Hello everyone,

we are currently a bit at a loss as to how best to approach the topic of financing and construction planning.

Starting point:
We have the opportunity to build in my parents-in-law's garden (their property covers approx. 1,800 sqm [existierender Bebauungsplan in dem Gebiet], of which we would separate 600 sqm for ourselves).
An initial inquiry with the responsible city employee for the land use plans etc. has already been positively acknowledged, now we are supposed to create a plan for him showing what kind of building and in which area of the property we imagine.
The city employee has also already gotten an impression of the property and explained to us how/from where supply and disposal lines need to be laid, from where access would be possible, etc.
Estimated costs by him - lines 30,000 EUR (approx. 30m connection length), 10,000 EUR "bureaucracy."

Now it is the case that our part of the property would be bequeathed as an early inheritance to my wife and her two siblings, and we will pay them out.
With a land value of 265 EUR + 600 sqm, the property has a value of 159,000 EUR, hence we would have to pay out the two of them accordingly, each with 53,000 EUR. (Both siblings agree!)

Since, due to the division of the property etc., it will take a little while before we can start building, the question now naturally arises as to how best to approach financing.

Equity cash funds: approx. 50,000 EUR
Financing needs for property: 2x 53,000 EUR + approx. 40,000 development = 146,000 EUR
"Equity our inheritance share" = 53,000 EUR

Rough plan for the house:
- 130 sqm living space, 1.5 floors, gable roof, approx. 8x10 m footprint, no basement, carport, no garage. Rough estimated value 300,000 EUR
- Property has clay soil, very slight slope (approx. 40 cm over the building width of 10 m)

Of course, we could already use up our equity to pay out one sister, and then go into the financing of the construction with 106,000 EUR "property equity."
But since the wheels of the city grind slowly, we were already given a rough timeline of 12-18 months by the city until we could start building.
Does an interim financing make sense over such a long period?

How would you approach such a project best?
I am grateful for any experience/assessment I can receive from you.
Thank you!

How would you approach such a project best?

Plan everything completely and then finance it or transfer the property. All in one go.

For 12-18 months, I would also suggest the approach from nordanney. If it takes longer and the standard land value rises, a variable interim financing through the bank (or through the siblings*) could also make sense. The standard land value always lags behind the actual prices. With prices having risen so far, this would mean that the standard land value will also increase in the near future.

Strictly speaking, the standard land value does not correspond to the market value. Consequently, the standard land value is probably the wrong basis for the payout, as it is likely significantly too low. If the siblings agree, all the better for you.

*e.g. 50% payout immediately and 50% as an interest-bearing loan until the arrangement of the overall financing)

Thank you both very much :)
Just now the email from the building authority arrived with the excerpt from the land register and the offer that we can sit down with him and the colleagues from civil engineering soon to discuss the details and costs!

You are absolutely right about the land value/market value, it should definitely be set much higher here, as it is a very popular building area and the plot is the prime piece - however, my parents would never let anyone other than one of their children build on it. But basically, the suggestion that we should/can build there also came from the siblings, as they both know how long we have been searching and they themselves already own property. The suggestion with the standard land value 2021 (which is 25 EUR higher than in 2020) also came from their side, so there should be no conflict there within the next 12-18 months :)

How would you approach such a project best?

Definitely do some thorough reading here first. We have similar cases about three times a year, and quite a lot comes together where basically all aspects have already been examined at some point.

I agree, everything directly at once.

How quickly do the siblings want the money in their account? The faster you pay out, the less potential for disputes over possible increases in value, etc., there is, and no one can change their mind later. But if you maintain and can keep a very good relationship despite these amounts of money, then a payout as late as possible wouldn't be wrong either.