Bus stops (and street corners) were added in some locations as an experiment to Pokémon GO.
This doesn’t mean all bus stops are automatically eligible. They still need to be a great place to explore, or exercise or be social with others.
I don’t think that if it’s just a bus stop with a timetable it would meet any of those so I would reject. Even the more “significant” ones you mention, people aren’t going there to be social like they might at a cafe. Maybe they’ll speak to a few people whilst waiting but I wouldn’t say to a friend to meet up at the bus stop to chat so would also say those don’t meet criteria.
Murals at the locations would be different as the focus is the mural, not the bus stop.
As for other locations, we have some tram stations that have been added, and we also have as mentioned, some larger transport hubs that are served by multiple buses and may have cafes and other things inside.