Buying a plot of land where a house previously burned down. What should be considered?

Hello everyone, we are shortly before the notary appointment to purchase a hillside property on which a house previously burned down. On the property stood 1.5 floors on a basement made of solid concrete (built 1989). Since only the roof structure and part of the ground floor burned, the basement was only affected by the firefighting water. After that, everything except the basement was demolished and the basement was protected with a roof made of tarpaulins. The property is being sold privately and is at the same price level as a comparable undeveloped building plot next door. Unlike the plot next door, we hope to save money through the still partially intact, developed basement, as well as the earthworks already completed. "The house burned very well because it was almost entirely wood," according to the fire department. Nevertheless, we are concerned about possible pollutants in the soil and unforeseeable bureaucratic efforts in planning or at the offices. The "basement roof" is an 11.57x11.57m flat concrete surface with openings for the staircase, heating pipes & 2 sewage pipes. Since the fire was already 1 year ago, the walls have already dried well (measured with a device). What else should we pay attention to? Here are some pictures (dark spots on the wall are not mold but soot residues)

tear down, dispose

Have an expert for fire damage take a look.

Even in minor house fires, an expert should assess which renovations are necessary and who is authorized to carry them out.

The soot from fires often contains bound, partially highly toxic substances that are formed.

I think calling it a demolition is exaggerated, the insurance of the former owner specifically demanded that the basement be maintained...? With limited capital, I find it illogical to tear down the basement and basically rebuild the same one without soot again. But I also think an expert is sensible, maybe we should really have one come. We were on site with an architect who has been active for many years, he actually had no concerns about the fire and otherwise you often read that after a fire the building is rebuilt. Especially with a wooden house built in 1989, there couldn't have been that many pollutants, or could there have been?

How about the smell of smoke? Is there still anything noticeable in the basement?

What about the smell of smoke? Is anything still noticeable in the cellar?

No, there is no smell, I paid special attention to that because I wanted to be sure that the walls are nowhere damp/musty or moldy. The fire itself did not reach the cellar directly but only indirectly via the running down rinse water.