If you have oil fired steam rather than coal fired steam, what activities are no longer needed?
There's basically no ash and clinker to deal with on the depot, and liquid fuels are generally easier to handle and store. For cost reasons, oil-fired locos of old generally used very heavy, thick, fuel oil - basically almost refinery residue - which has to be heated to flow easily, but that's not a problem with a hot steam supply to hand. They still needed a fireman to look after the boiler, but obviously that's an easier job than shovelling coal into the firebox. Otherwise it's basically the same loco from a servicing point-of-view.
One thing that is easily possible with liquid fuels is having multiple tenders, as fuel and water just need pipes to get them to the firebox and boiler, so there is potential for much longer runs between servicing stops (e.g. the now oil-fired UP Big Boy #4014 normally pulls three tenders behind it - one black, two yellow). Also it's possible to turn the loco around and put the cab at the front e.g. see SP 'Cab Forwards' -
https://en.wikipedia.org/wiki/Cab_forward
Training was a major one - in some quarters it was perceived as far too short - and of course there were many issues involving what to do with those jobs that were no longer necessary (everyone knows about the demise of the secondman).
Yes, but that's just normal management and industrial relations stuff, nothing directly to do with the technology - the change to electric and diesel was going to happen anyway at some point, given that both electric and diesel traction were well established technologies by 1950. In a competitive environment, if you don't embrace change, you'll die out eventually (it's called evolution, like nature does...).