Is it possible to build or extend a house in an industrial/commercial area?

Hello everyone,
I would like to build at my parents' place in Lower Saxony.
It is a commercial area GI.

A request was made to the municipality to build behind my parents' house.
The answer was:
“At the location you requested, residential construction is not possible.
All areas shown in “gray” are industrial areas, as can be seen from the development plan. The “blue” marked line indicates the building boundary. No area is designated for residential space in the development plan. I can only recommend consulting an architect.”
This means to me that an architect might have a solution for how building could still be possible? The houses were originally built for managers, etc., from the neighboring company, and demolition and new construction is probably not permitted.

I also have the opportunity to buy land from the neighbor. Would it be easier if I “attach” next to my parents, meaning build a garage between both houses?
Attached are some pictures for illustration.

I am grateful for any help.

Check with the building authority about an extension; depending on the answer, you will see if anything is possible at all.

Ask the building authority about an extension; depending on the answer, you'll see whether anything is possible at all.

Just the statement from the municipality tells me that I have to prove to them that construction would be possible. Therefore, I want to gather information elsewhere first before I approach the building authority or similar again.

As far as I know, living in the industrial area is only possible in exceptional cases. I have even heard of cases where people were thrown out of their apartments after many years. Maybe it’s better not to wake sleeping dogs.

§8 (3) 1. The Building Use Ordinance says (regarding commercial areas, and here we are even talking about a GI): "Exceptionally, apartments may be permitted for supervisory and on-call personnel as well as for business owners and managers who are assigned to the commercial operation and subordinate to it in terms of floor area and building volume," and in VG Augsburg, judgment of 18.08.2016 – Au 5 K 16.577, a managing director was rejected when trying to continue using the residential building constructed for her operations manager. In short: don't get your hopes up too high.

I also have the option to buy land from the neighbor. Would it be easier if I "extend" next to my parents, i.e., put a garage between both houses?

No. I do not see a manager's apartment for your business on the neighboring business’s property, and linking the building structures will not change the situation.

Alright, apparently there are no other opinions. I will take the risk anyway. I just find it unfair if it is not possible. Then you also cannot get rid of the property under the current situation.