Order of soil survey, building permit, prefabricated house order?

Hello everyone.

My prefabricated house provider has a delivery time of 8-10 months due to material shortages. Therefore, I am thinking about what to do until I can order the house, so that the house is ready by next summer. So far, there are only thoughts in one head: location and orientation of the building, rough cost calculation, type of prefabricated house.

1. Prefabricated house delivery time: 8-10 months

2. Building permit: 2-3 months waiting time
Should probably go quickly in my region (rural, building plot has been assessed as "approvable" by the building authority - response time 1 day)

3. Soil survey: Valid only 6 months?
To my knowledge necessary to get, for example, a foundation offer prepared. Groundwater (well next to the house) is only about 1.5 m deep, soil is very moist.
Attention: There is currently still a wooden shed on the future building plot with an approximately 70-year-old agricultural (self-poured) foundation.

Now I ask myself:
A) What is the order of 1/2/3? If I do a soil survey in July, it expires by December, right? If the building permit is granted, for example, in January, the prefabricated house is erected, for example, in April, and the foundation is "built," for example, in March. (Drying times set aside)

B) Can the soil survey be done if there is still an old building standing there? The old building is about 6x12 meters and the new one about 6x6 meters, roughly in the middle of the old building.