You can see various pictures and statues of Banjo-Kazooie's 'Mumbo Jumbo' in the rooms of the mansion.

Whenever you fight a "Ghoulie", listen. They often sound like creatures from Banjo-Kazooie.

Every time you enter the kitchen where Ma Soupswill is located, look on the billboard near one of the kitchen's doors. You will see a picture of Banjo and Kazooie.