Timeline of real estate acquisition tax and house construction contract

Planned completion of development Q3 2018 means no one will build there before 2019.

Why? For us, the approval was on April 1st and on March 31st there were already enough excavators parked on the plots.

And the contract can definitely be signed. Subject to financing. It shouldn't actually be too big of a problem. However, the contractor will of course factor in a certain risk surcharge.

Q3 2018 is still almost a year away. Until then, there will be plenty of delays. But the OP has by now the information that it can already start next spring.

The start of construction is dictated by the BU and the building permit, not by the property seller. The latter can talk a lot!