My own experience - others may vary.

I've never been in a church which provided music copies for everyone in the congregation. Applies to both established and non-established churches. Those who really like to see the music bring their own music copies of the hymn books. The choir will have music copies.

The organist can choose which tune to play, but for most hymns the congregation will expect the 'usual' tune; for some hymns there are two or three tunes that can be chosen. Sometimes the person leading the service will ask for a specific tune, usually before the service, so the organist knows what's coming. Situation is exactly the same for accompanists other than the organist.

Harmonies usually come from tradition, or from the choir, so are learned by osmosis, rather than taught. New hymns / worship[ songs may be taught a bit the first time, but is't usually a case of follow a strong lead, and pick it up as you can.

This based on a variety of Baptist, Presbetyrian and (very) low Anglican. Others may have different experiences.

Bradypus