Are Southern Buddhism and Northern Buddhism the same? Regarding the Buddhist ideal model for practitioners, is there any difference between Southern Buddhism and Northern Buddhism?
I could see some similarities in the Theravada  Mahayana Doctrines.

Mahayana and Theravada

Both rejected the idea of a supreme being who created and governed this world.

The Four Noble Truths are exactly the same in both schools. 

Both Mahayana and Theravada doctrines help us to not being influenced by the objects of the six senses. In Mahayana they call it the becoming of Buddha Nature – to be awakened. We call it being an “Arya Shrawaka” in being a part of the ideal community of Noble Ones (ariya-sangha)

The Eightfold Path is exactly the same in both schools. ‘Paramita’ in Mahayana is this ‘crossing over’ and ‘reaching the other shore’ in walking the eightfold path.

The Paticca-samuppada or the Dependent Origination is the same in both schools.

Both accept Anicca, Dukkha, Anatta and Sila, Samadhi, Panna without any difference.