The fact that it is hotter, lighter, smaller, larger or a different
color does not influence its rising without the consideration of the
denser air around it.

Yes it is "LIGHTER" than the air around it, that's what LIGHTER
means.

The balloon rises because it is displaced by the denser air around it.

No the balloon rises because the ambient pressure at the bottom of
the balloon is higher than the ambient pressure at the top. The
difference between these pressure forces is equal to the weight of the
displaced air. If the weight of the balloon is less than that
displaced weight, then the balloon rises. The only way that happens
is if the balloon is LIGHTER than the displaced air.

What did you think that the balloon (or thermals) was supposed to be
LIGHTER than ? Your shoe ? A car

Please read up http://en.wikipedia.org/wiki/Buoyancy before you try
and re-invent physics.
Or better yet, go fly somewhere.

Todd Smith
3S