The two pictures I've shown are the two ends of a 4 mile route. The one 'high speed' section past Judkin's Point is maybe a quarter mile long. More conventional buses serve the rest of the area, and often at highway speeds.
I think the mirror's are similar. The local fire departments also use them, hung from the ends of stalks that move the mirror out of the area around the A-pillar. So while I think it's for visibility, there is some aerodynamic advantage there.
Above that panel break that runs above the side doors is all air conditioning and IIRC hybrid batteries.