What to consider regarding rear construction, narrow access paths, and co-ownership

I am currently considering buying a plot of land in the 2nd row. There are presumably a number of things to consider, which I do not fully oversee and also do not know exactly how to best secure.

The plot:
just under 800 sqm in the second row with a development plan.
When purchasing, 50% MEA of the access road (just under 45m x 3m) is additionally acquired. The other 50% belongs to the owner of the front plot.

Along the access road, on one side is the house of the front plot and behind it a garage. The access road should have exactly 3m width. Currently, there is still a small wall pillar in the driveway, so currently, there is no 3m width there.

The sales advertisement states the obligation that after laying the house connections, the access road must be restored.

Now to my questions/problems:

1. Since a large part of the plot is more than 50m from the public access road, I need a fire department access road, which according to the state building code must have a clear width of 3m and a height of 3.5m (+ maneuvering space).
I am a bit "afraid" that during the survey it might turn out that the access road is not quite 3m wide. Can one then demand a reversal or similar?

2. The driveway/access road must be restored: However, the wall pillar must definitely be removed to guarantee the 3m for the fire department. How and where would this be agreed upon? An additional contract with the other owner? And the signing of the contract as a condition for the purchase contract of the plot?

3. Should further rights of way be registered on the access road? I am only 50% owner, so in principle I could be blocked by the other owner in decisions. Can formulations be included such as "The access road is to be permanently constructed as a paved fire department access road"? Maintenance costs would always be shared? Even if only I have an interest in the complete access road.

4. Basically, the access road will have to be changed. That means trees felled and paved instead. I have to discuss this with the other owner in principle? Can he object?

5. What else do I need to pay attention to? I have already read about the depth of the sewage pipe. Other things that are often overlooked?

You need space to build. And trucks that come to your property. Allocate space for the crane, etc.

I don’t quite understand your contract situation with 50%. Often the owner remains the owner and the rear party gets a registered right of way and applies for a construction burden for supply and disposal on foreign ground.

Whoever bears the costs for access, pillars, maintenance, etc. should all be regulated in the notarized sales contract.

I am a bit "afraid" that the survey will show that the access road is not quite 3m wide. Can one then demand a reversal or similar?

Only if agreed in the purchase contract.

2. The driveway/access road must be restored: However, the wall pillar definitely has to go to guarantee the 3m for the fire department. How and where would this be coordinated? An additional contract with the other owner? And signing the contract as a condition for the purchase contract of the plot?

First talk to the other owner.

3. Should further easements be registered on the access road?

That is not necessary. The rule that an access belongs to multiple parties is common.

4. Basically, the access will have to be changed. Meaning trees will be cut down and paved instead. I have to basically coordinate this with the other owner, right? Can he object?

Same here: Talk to each other and simply agree in advance. Changing things arbitrarily is difficult.

You need space to build. And trucks that come to your property. Plan space for the crane, etc.

I don’t quite understand your contract situation with 50%. Often the owner remains the owner and the other party obtains a registered right of way and applies for a construction burden for supply and disposal on foreign land.

Whoever bears the costs for access, pillars, maintenance, etc., should all be regulated in the notarized purchase contract.

That’s why I explicitly mentioned it. The owner of the access road effectively gives up 50% and I will become a co-owner. The reason is certainly cost sharing.
I just have the feeling that despite this acquisition of ownership, one should by no means forgo the registration of a right of way. Because with 50%, he could block all decisions, right?
The parcel is initially only urgently to be declared as access from my point of view. It is not designated as such in the development plan or similar. The other owner might prefer to see just a meadow there and no paved surface.

Talk to the other owner first.

That is not necessary. The regulation that an access belongs to several parties is common.

Of course, I will speak with the owner. But that does not result in a binding contract that I can still enforce against someone in 30 years. I wonder where such agreements are contractually recorded.

Only from that does no binding contract arise afterwards that I can still throw in someone's face in 30 years.

You can include provisions in the purchase contract and agree that these are inherited by the next buyers.

I would: 1. Only buy if there is a high probability of a good neighborhood 2. have the access road registered in the land register as a separate parcel and enter a declaration of indivisibility. 3. Expect increased construction costs if the access is a logistical challenge 4. Fairly allocate the costs for the access road proportionally to the owners and have this contractually recorded. 5. I would build the house exclusively on land that is 100% owned by me - in case the land shares also affect the building plot.