I put character lists here and if you like comment your cast suggestions please in comments

O'Neils & Rosarios

Tristan + Vienna = Nathan and Natalia (Twins).... and Nicandro

Vincenzo + Terza = Leandro and Lavinia (twins) and Leo

Rossi Family

Michangelo and Arcangelo Rossi (brothers)

Rafaela Rossi (their aunt)

Rupert Rossi (their father)

Tatiana Rossi (Their Mother)

Roman Rossi (Their uncle)

Others

Sebastiano Giovanni (son of Sergio Giovanni who is Sancia's brother) has a son called Rocco

Nicholas is son of Trent

Austin is son of Angelo Lombardi who is Adele's brother ...

Adele + Francesco = Vincenzo and Viggo and Vienna

Vincenzo is father of Lavinia, Leandro and Leo

Sancia + Terence Emmanuel O'Neil = Tristan and Trent and Clarissa

Tristan is father of Nicandro and Nathan and Natalia