is rebase the same as merging every commit?

Rebasing is described in the docs I've read as turning this: (sorry for the
dots)

..........A---B---C topic
........./
....D---E---F---G master

Into this:

...................A'--B'--C' topic
................../
.....D---E---F---G master

If I understand it right (and that's a BIG if), it's the same as doing a merge
of C into G where every individual commit in the C-line is individually
committed into the new C' line.

...........-------------A---B---C
........../            /   /   /
........./        /---A'--B'--C'  topic
......../        /
....D---E---F---G - master


(1) Is the above model a valid explanation?

(2) From the documentation diagrams, it looks like the rebased A' has only (G)
as a parent, not (A,G). If this is the case, why?  (i.e. not connecting those
nodes throws away useful information)

(3) If it only has (G) as a parent, does the rebase explicitly remove the
source A,B,C nodes from the repository? (the diagrams make it look like it
does) ..or do they just get cleaned up during GC?