Which chapter did they say it can be ANYONE? I'm pretty sure it's only in Gantz's memory. The reason why Tae got ressed is because she was in Gantz's memory since she got scanned when she was terminated in her mission.
And -san is like Mr. Mrs. or Ms. , it's very common, standard formal.
-dono is very rarely used as it's more like a historical thing like Sir or something
-sama is respectful, someone you greatly respect.
-chan is for very little children or as a pet name like baby
-kun is for kids/teenagers like 12-18
there are probably some others that I don't know but it's just adding a title to someone's name.
Also calling someone by their first name is also seen as very intimate same with just their last name (without adding -san or -kun).
Back from ban-hood, I blame explosm webcomics