Does the residential apartment you live in and own become part of the inheritance distributed to the heirs after your death, or does it remain for the wife and daughters without being counted as part of the inheritance? And is writing it in their name during your lifetime considered unlawful (haram)?

The apartment is part of the inheritance, and all heirs are entitled to it according to the Sharia-compliant division of the estate.

If the apartment was registered in the name of the wife and daughters as a will, then it is a bequest to an heir. However, if you transferred ownership to them and released it from your possessions for them, and they took possession of it during your lifetime, then this is a gift.