Wait with the building application because of the child construction allowance

My wife owns a residential unit in a student dormitory. Of course, we could never move in there; it’s purely an investment. Nevertheless, it is of course registered in the land register and she receives rent. Do you think this is a disqualifying factor because it is a "residential property"?

If you have more than one child, you can trick it a bit Sell, give away primarily (will be free of charge and no real estate transfer tax applies) Then apply for Baukindergeld and after approval have the apartment given back. With 2 children the hassle is worth it

If you have more than one child you can trick a bit there Sell, give away primarily (will be free of charge and no real estate transfer tax will be incurred)

Is that even possible? Isn't that fraud or something? But it's probably too late anyway. As far as I know, the cut-off date here is the notary appointment.
This matter still doesn't let me rest.
From the KFW information sheet:
"As long as your household (applicant as well as spouse or partner in a marriage-like community or children) already owns a self-used, rented, usufructuated, gratuitously assigned or vacant residential property in Germany for permanent use, funding with the Baukindergeld is not possible."
I don't think the student apartment meets this definition.

Edit: Now that I read my own quote again, I realized that the children must not own property either. Others have already come up with that idea.