Hello Aidan, not silly questions at all. If your GGUncle was a bus conductor living in Yardley (where exactly??) in 1901, it is likely that he worked for one of the many private bus operators who ran services in the early days of public transport, most of whom were eventually taken over by the growing BET bus empire as has been documented earlier in this thread, which later became the motorised BMMO (Midland Red) company as the first war approached. The main BET horse bus depot was in Bearwood, on the later site of Midland Red's Bearwood Road garage and workshops, now covered by a supermarket - so I doubt if he travelled daily to work there.
As to the pictures, the first one has Tilling Stevens buses with 'OE' and 'OH' registrations, which date from 1919/20 - sadly the crews are blocking the view of the second and third vehicles, which are lower than the buses and are probably charabanc bodies on similar chassis. The second is easier - enough of the registration is showing to identify it as HA 2351, a 1923 SOS standard chassis (built by Midland Red themselves) carrying a Davidson of Manchester 32 seat charabanc body. This was withdrawn from service in 1928, so dating the picture to a five year span. These were fast vehicles capable of 45-50 MPH on the open road (although restricted by the law to a meanial 20 MPH), built to be lighter, faster and more comfortable than earlier designs by other manufacturers, which were often based on lorry chassis design and running on solid tyres. One daunting thought though is that they had rear wheel brakes only, and could probably accelerate faster than they could slow down!
Lists of employees tended to be regularly amended or destroyed as staff changed, and for most cases the employee would have a 'file' which would be thrown out soon after he had left. Coach drivers were chosen based on seniority, good driving record and good character qualities, so his status shows him to be of high standing with the bosses!
It is possible knowing the records you have of him via censuses etc that he joined the Midland Red on demob from the army, an ability to drive (and for army drivers that included fairly detailed mechanical knowledge) would have been a good leg-up to his career, possibly with references from his service with the horse bus company.