Planning costs for demolition and clearing

Thank you for all your answers. That already helps a lot.

Now I would be interested to know if you have more reference data on (1) - the demolition.

Can one with a clear conscience assume that the demolition of the existing house with side shed (including basement) in no way exceeds 40k€ (provided there are no other special features)?

Get quotes from demolition companies. A major cost factor is disposal. Not every landfill is allowed to accept every pollutant class. Then it can potentially become really expensive. The pollutant class is only determined once everything is in one pile and properly examined in the lab. Talk to several. We had everything from 40k to 100k back then. However, more rubble than you have.

Clearing and disposing of 2700 sqm, demolishing and disposing of 2 cellars, a pit with used oil including disposal + leveling the site = 40K in January this year. Property in the far east of the country.

Thank you Katja! I will also take the numbers as a reference.