Must a girl visit her abusive father despite the objections of her mother and siblings and the potential deterioration of her family relationships that this might cause, or should she suffice with speaking to him via phone, especially since he harms her with his words?

The daughter is obligated to be dutiful to her parents. If the mother’s command conflicts with the father’s, such that reconciliation is impossible, the mother’s command takes precedence. In this situation, the daughter should visit her father without her mother's knowledge and maintain ties with him in a way that does not harm the mother.