Steeling Blood Clarification

When playing combat cards that steel blood, the blood is stolen before damage resolution, with excess blood removed, and then regular damage applied to the vampire that stole blood? Correct?

Yes.

See the Rules Reference [6.4.3]

iv.Steal blood. Removes blood/life from the opponent and places it on this vampire. Blood in excess of this vampire's capacity is burned immediately. Stolen blood may be used in step c. [6.4.5]

c.Prevent damage and then resolve any unprevented damage (VII).

Correct.

Let's give a useful example:

A Shambling Hordes (4 life, hence 4 strength)is in combat with Carna (6 blood) .
Range is close.
Shambling Hordes (4 strength at this moment) declares a handstrike. This handstrike is for 4.
Carna declares a Theft of Vitae at superior.
Now, we move to strike resolution.
Strikes resolve simultaneously, so the Hordes punch Carna as she steals 2. Damage will be resolved later.
Carna gets 2 blood, making 1 blood drain off, and the Hordes drop down to 2 life. The Hordes' strike remains a handstrike for 4.
We now resolve the damage. Carna plays no prevention card, and burns 4 blood for the 4 damage inflicted by the Hordes.
There is no press, and the combat ends.
Carna now has 3 blood, and the Hordes 2.