Well, speaking for
Urbis ...
1.) How common is a level of education for the NPCs (and PCs) in your game world?
Some very basic reading and writing is common among the masses - the urban poor read very slowly, and most of them would have read problems if their index fingers were cut off, but they can do it well enough to read official pronouncements and instructions.
2.) Are only the elite spellcasters educated, but perhaps only in their field?
Wizards are considered craftsmen, if highly-paid ones. Clerics who are part of an organized religion get a very good, if biased, ecucation, while clerics who aren't learn in a more haphazard way, just as bards and sorcerers. Druids are mostly educated in the ways of the wild, but since they are on the retreat, much knowledge has been lost.
3.) Do nobles benefit from higher learning, or perhaps just the basics?
They recieve the best education possible. Politics are
devious in Urbis, and a good education will increase your odds of survival far more than swordsmanship ever could. Same goes for non-noble members of ruling families - the aristocracy didn't survive the rise of the city-states in all regions.
4.) Do experts have schools for their specialties?
Yes, and they try to make damn sure that these schools retain a monopoly - if their knowledge becomes too common, they'd sink in status and possibly join the unwashed masses.
They don't always succeed, though...
5.) Are there trade schools for craftsmen or just apprenticeships (and how formal are they)?
There are, but many are under increasing pressures from new factories who use unskilled labor to produce goods. It's pretty much the same as during the Industrial Age...
6.) Do commoners ever see the inside of a classroom?
Depends on how poor they are. There are schools open for the general public, but if the family is too poor, the children are sent to work somewhere to pay the rent...
7.) What sort of training beyond the tilting field is received by guards, warriors, and soldiers?
Whatever the one who hires them is willing to afford. Some city-states have professional military training, while others are content to hire mercenaries...
8.) Do bards learn exclusively from a single master, or are there dormatories with some of the best damned parties in the kingdom full of them?
Depends. Some learn from a single master, but there are also "Entertainer's guild", and in recent decades some nobles and other rich families have started to educate their children in the basics of the bardic arts - after all, influencing lots of people is a very useful skill for a ruler...
9.) Where do monks learn their many disciplines?
Monk in Western regions are in decline, and most belong to beggar orders, which means they enter an apprenticeship under a single master. But they can also recieve training in far-off lands where large monastic orders still exist.
10.) Does every temple have a classroom for their clergy?
If it's an organized religion, they are likely to have a theological college somewhere. If not, their temple likely isn't large enough for organized education of initiates.