> The point is to remove Hamas from a position of power. If that happens with fewer casualties, do they then continue war and kill a few more just to be "proportionate"?

Proportionality is a maximum limitation in just war theory, not a measure of minimum acceptable violence. (The same is generally true in more personal law when proportionality is a component of self-defense provisions.)

> Also regard 2, if you genuinely feel your cause is just, the result you want is unconditional surrender.

No, you want a resolution with acceptable conditions which align with your cause: unconditional surrender necessarily achieves that, but it is by no means generally necessary.