What is the ruling on acquiring and keeping pictures and statues of animate beings not intended for use, and what is the ruling on hanging drawn heads?

There is no objection to the toys you mentioned, as the Sunnah indicates the permissibility of children's play that takes the form of animate objects. This includes both males and females. Al-Qadi 'Iyad reported the permissibility of this from scholars, and Al-Nawawi followed him. The reason for this is to train children in matters of upbringing, to entertain and delight them, and to strengthen their activity. What confirms this permissibility is the Hadith of Al-Rabi' bint Mu'awwidh Al-Ansariyah.