Laminate in the basement, what speaks against it?

"I would now lay impact sound insulation with Aquastop under the laminate. Is there anything against this plan?"
Answer:
No, there is nothing against it!
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"Would you transfer the joint between the two screed areas into the laminate or simply lay over it? Could the laying direction possibly make a difference here?"
Answer:
Since it is a floating installation and the room size is limited, you can lay it continuously. Although this does not correspond to the general installation guidelines of the manufacturers, if later on tension-related buckling occurs in the surface, you can easily cut the joint in the covering and separate the area with little effort.
The laying direction is not entirely insignificant, but in this case, it will actually cause no problems in practice (given the room size).
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Good success: KlaRA

Is there anything against this plan? Would you incorporate the joint between the two screed areas into the laminate or just lay it over? Does the laying direction possibly make a difference here?

There is nothing against it, the joint doesn’t matter as long as you don’t glue it, and the laying direction is a matter of taste, it can make the room look longer or wider. In case of water damage, you just replace the floor, with tiles you avoid that. But how often do you really have water damage in the basement of a new building...