Securing supply lines during demolition

We have the same situation. You have to get in touch with the utility providers.
Water: The provider told us that they no longer use the old pipes, too old, too small diameter, so they will be shut off and have to be newly laid. Funny was that the provider didn’t even know where the pipe runs, they had to look for it first.
Wastewater we had laid ourselves many years ago, we separate that outside the house to be demolished and then simply reconnect with the new pipes.
Electricity: done by the electrician of the construction company, apparently you’re not allowed to do that alone. But he only applies for the relocation, so we don’t need extra expensive construction electricity, but can stay with our provider.
Telephone: we are lucky that our connection is in the garage, which stays. So that can simply remain and will just be re-laid into the house.

But basically you coordinate all that with the construction company.

I roughly sketched it out in the attached file ...
The basement is to be completely excavated, filled, and compacted for the foundation slab ...

I don't see anything attached. My question was aimed at what advantage the deep demolition should have or whether the basement is disturbing: even if it is too small, misplaced, or too high, deep demolition is not always the most practical solution.

It's not necessarily that tragic. Some of the old walls are still standing here. Under the kitchen, the sandstone from the manure pit and half of the potato cellar are still there by the farm entrance.

Actually, the demolition company takes care of the connections. Or did we buy a all-round worry-free package there?