Do all applicants who immigrate to Australia need an interview?

No need. At present, all Australian immigrants submit electronic visas. Except for business visas, which have a very small probability (less than 20% probability) of being "invited to tea", other types of visas do not require interviews.

Moreover, different types of immigrant visas are processed in different places: student visas are submitted at the Adelaide Student Visa Center, business visas are submitted at the China-Hong Kong Investment Immigration Visa Center, skilled immigrants are processed in Brisbane and Adelaide (immigration officers of BNE Group and ADL Group, which are popular online), and parents' visas are submitted at the Parents' Immigration Visa Center in Perth.

Therefore, if the Immigration Bureau wants to further investigate you, it will only refer you to an overseas post, such as an embassy in Beijing or Shanghai, so that the staff of the embassy can carry out the investigation. Most immigration offices only conduct simple telephone background checks.