1 - Cloud defeats Sephiroth in his mind so that he cannot control him anymore.

2 - The team gets out of the North Crater.

3 - Meteor is about to collide with the world.

4 - Holy stops Meteor, but is not strong enough.

5 - Lifestream helps Holy and destroys Meteor.

6 - Aeris's image is shown as if to say that she directed Lifestream.

7 - Red XIII and his offspring are shown as if to say that the planet has still not died after many years, and is infact recuperating.

EDIT: Before dying, Bugenhagen tells Nanaki that he would probably find his mate out there somewhere. He just had to look. It was probably thought that he was the last of his kind, but there was probably a female of his kind somewhere in the world which he later on finds.