In a countdown in German, it is “eins , zwei, drei, etc”, so that is a mistake. But House of Gaga is the publishing company, not her creative team (which is Haus of Gaga), so that is not a mistake.

House of Gaga in the closing credits is NOT a misspelling, because that is the name of Lady Gaga's publishing company (which is owned by her father). The Haus of Gaga is her creative team.