With regards to vertical gusts...

A stable aircraft will react to this by pitching down
and increasing its airspeed

I thought a stable aircraft has the C.G. forward of the center
of lift. If this is so, and this effect only happens if
the aircraft is stable, then C.G. is important, right?

If the C.G. and center of lift coincide, does this effect
still occur? If the C.G. is behind the center of lift (my
understanding of "unstable") does this occur?

Martin has interesting points, but I'm not understanding
them just yet (it may be I don't understand the
terminology quite yet...)