Regarding the fauna, in any cruise it is possible to see Gentoo, Chinstrap and Adelie penguins. The king penguin can be seen if the itinerary includes the South Georgia Islands. To see emperor penguins you will have to hire a specialized cruise that arrives more to the south than regular cruises and offers this kind of visits.
It is also possible to see humpback whales, the Minke whales and the Antarctic killer whales, leopard seals, albatrosses and cormorants among other birds.