Property / Building Authority Data - Monument Authority - Drainage Indications

Hello everyone.

A new building plot has become available to us. This will be freed up by the subdivision of a currently developed property.

There is also a positive preliminary approval from 2012, which was not extended. I assume that this can be renewed. For this purpose, I will contact the building authority.

Now there are various comments in this preliminary approval, which I have attached below for you. Furthermore, you will find the parcel where the property boundary still has to be drawn in. This is located between the planned and the existing building (6 m distance) on the 3 m line, parallel to the existing building.
An overview from Google Maps and pictures of the property (trees) are also attached.

The following questions arise for me:

Drainage:
It states there that the drainage can be managed via the small sewage treatment plant of the existing building, but it must first be ensured that it is sufficient.
However, the existing building is currently being sold. What if the purchaser does not want me to use their pipes? Does this have to be recorded in the land register?
It is possible to build a separate sewage treatment plant. What are the distances to residential buildings in this case? I also wonder whether these plants smell unpleasant. My grandparents have a sewage and lift station on a hillside property, and it sometimes smells very unpleasant.
And finally, the costs - I find roughly 6-10k on the internet for the complete system including installation. Is that realistic?

Monument protection:
If a finding is actually discovered during earthworks and the colleagues from the monument protection authority have to come out and this significantly delays or makes construction impossible, what happens then? That I will ultimately be responsible is clearly stated in the letter.

Fencing:
The letter states that the property must be fenced off against the state road on the cadastral boundary without door or gate openings. Are there height restrictions for, for example, hedges or fences? At the same time, point 7 insists on a visibility triangle. This speaks of a leg length of 70 m and 3 m from the edge of the roadway. Does that concretely mean that the entire property on the south side loses 3 m because the hedge, if it is to be over 70 cm high, must be placed in front of that?

Immissions:
What could point 8 mean? What measures could these be?

Tree stock:
There are some large trees on the western boundary. These would all have to be felled. Am I allowed to do that just like that? After all, the connection is supposed to take place via this side.
Can anyone estimate how costly it is to fell the trees?

Unfortunately, I am not very well-versed in these matters, as the previous properties were all much simpler. I hope you can help me a bit.

Thanks in advance!

Does this have to be recorded in the land register?

No, but that would be the safest place.

Are there height restrictions for e.g. hedges or fences?

Without a development plan or other local building regulations, usually only those that come from road law. That would be 70cm in the area of the visibility triangle.

that the entire property on the south side loses 3 m

No. Something like this:

What could point 8. mean?

Noise protection

What measures could that be?

Expensive windows.

Am I allowed to do that simply?

You have to ask the municipality. Most have a tree protection ordinance nowadays. In addition, the nature conservation laws (federal and state) must be observed.

Noise protection

That would not be a problem, at this point I would anyway opt for windows with higher sound insulation.

No. Something like this:

Who can tell me exactly? Probably the building authority as well?

I assume that this can be renewed.

No way. Since the preliminary decision was never used and extended, it is quite possible that an application will be rejected and it can no longer be built. I was advised to submit a (chargeable) inquiry!

Who can tell me exactly?

The surveyor, if he has accurately measured the roadside by local surveying. Perhaps the property is not even affected, as there is a wide green strip along the road, which most likely lies on the road property. Local surveying also reveals this.

I was told to submit a (paid) request!

Of course. You yourself spoke of "renewed", meaning redone. Since the legal situation has not changed significantly since 2012 (which should of course still be checked), rejection is rather unlikely.