A: The confusion arises from the fact that song mode displays "events" available, while other modes display RAM available in bytes.
A K2000 sequencer event uses a variable amount of memory, but for those that feel the need to know, I have estimated, that it uses about 4 bytes per event.
186k events use approx 744k bytes.

The largest that a Song object can be is 64k, or about 16k events. A note-on is considered one event, and a note-off is another, hence the largetst Song can contain about 8 thousand notes.