ᐅ Is the excavation suitable for backfilling?

Hello everyone,

I need to raise my terrace by about 70cm (28 inches) to make it level with our house. This will include 50cm (20 inches) of fill material and 20cm (8 inches) of topsoil, which corresponds roughly to 90 cubic meters (118 cubic yards) and 35 cubic meters (46 cubic yards). Permits are already in place.

I would like to have the fill material delivered from another construction site. There is a soil report available, which I will summarize as follows:

Here are some recent photos:

The soil is described by the owner as clayey. Do you think I can use this material safely for the fill? The note about soil moisture in the report is a bit concerning to me.

Additionally, below my retaining wall, there is a slope that levels out at the bottom. The area has been disturbed by wild boars. I want to roughly rototill it now so that I can later maintain it with a flail mower. Are there any appropriate machines available that can handle areas with stones?