I still tend to think that Drink's death on the first day was suicide. Your clues and the burned-down house also point to him.
Or maybe the clues are just very complex. In Mafia 6, they didn't solve almost anything.
Лидер клана "Из многих единое"
Приключения – это сплошные неприятности, только про них почему-то потом интересно вспоминать...