Include human users, batch accounts, and any non-human device (app server, feed) that connects — Oracle's Named User Plus definition counts both.
Every environment running the software counts — Production, DR/standby, and Dev/QA all need their own licensing unless a specific exception applies (e.g. the 10-day/year unlicensed failover exception).
Each option is licensed on the same metric and same processor/NUP count as the database beneath it — you can't option-license a subset of the cores.
Annual support is calculated on the net license price (post-discount) at 22%, per Oracle's standard technical support policy.