correct me if I’m wrong but I don’t think the second stage is meant to be caught. It will have legs to land on Earth/Mars without any landing infrastructure.
It will have legs for Mars but they plan on catching it on Earth.
It is expected to land astronauts on the Moon as well this decade, which will certainly require legs.
That is a different version. The ones launching/landing on Earth are supposed to be caught by arms similar to the booster.
The ones for other celestial bodies are also planned to return to Earth... Being inside one as it does the belly flop will be quite the experience.
Pretty sure the Artemis lunar missions are going to use a different vehicle for Earth to LEO and LEO to Earth, so I don’t think anyone will be inside a Starship belly flop for quite some time