Can anyone find the difference between current Likud members that gave their tacit support to the expulsion, and those that joined the Kadima party?

The answer is simple. There is none.

Yet Bibi wants to unilaterally expel Feiglin from the Likud.

So then what exactly differentiates a Feiglinless Likud from Kadima?
Absolutely nothing, except that Kadima has a stronger (despite his stroke), and certainly more popular (perhaps even more so due to his stroke) leader .

So then how exactly will the Likud distinguish itself as a Center-Right party?

Bibi gave away parts of Hebron. Limor Livnat, Shalom and others Likudniks (that still haven’t left Sharon’s government!) supported the expulsion. Besides Uzi Landau, who else has any surviving center-right-wing credentials left to distinguish them from Kadima?

Bibi has the opportunity to create a true center-right party, a party with values and goals, but instead he is trying to merely create a Kadima clone in an attempt to regain a few seats. A poor copy at that.