I asked a lot of those same questions of Tim at United Truck Body when I bought my bus from him. Here's the answers he gave me. While they might not be "by the book," it is what the majority of schools around here follow he said.
Fluid checks on the automatic tranny should be done with every pretrip.
Steering linkages should be inspected with every pretrip and lubed every oil change. There are grease zerks on mine.
U-joints should be greased at every oil change. Don't overfill them and inspect them for any looseness when you're under there. He said they should last 100,000+ miles
Gearlube is rarely changed. It's not that it shouldn't be....it just isn't. He said most mechanics just don't. They will add some as needed after doing an axle seal replacement, etc, but rarely is it done just for the sake of doing it. That said, I don't think you see all the many gear set failures either.
Tire pressure should be checked as part of every pretrip, but you know darn well it's generally just done by sight or with a quick thud on the sidewall with a club to hear it. I would check them before going on a long trip.
I know that information isn't the correct information, but I know it is what is practiced so take it for what it's worth. If anyone else out there has heard from mechanics, I'd love to hear it as well.
The starter problem sounds like a weak bendex. It's not the worst thing in the world. It's just annoying. You might be able to pull it apart and clean it if it is gunked up. If the spring is actually shot, most times they can just be replaced instead of getting a whole rebuilt alternator. I know the bendex on my little truck sticks all the time in the cold (not so much in the summer), but it doesn't really hurt anything. If it starts spinning and then suddenly engaging the flywheel on the bus you might want to get it fixed as that's a fine way to take out a tooth.