Multiple random questions

1. Strength refers to the Strength characteristic which comprises the Strength characteristic on the profile + any boni or mali the model might be subject to. So, "Slayers ignore penalties to Strength" includes penalties affecting the S bonus from their weapons. One can invoke a conflict between ABs, and dice it off, but, personally, I would be inclined to give preference to the Slayer special rule.

2. BRB p. 27: "Units that consist of a single model, such as monsters, chariots, lone characters or sole survivors of annihilated units, are mostly moved the same as other units.

They move, wheel and march just like a larger unit. The one exception is that a single model can pivot on the spot as many times as it wishes over the course of its move. It can do so without penalty and so pivoting does not prevent models from marching, or even from shooting later in the turn. This represents the greater freedom of movement that an individual creature enjoys over its fellows in a ranked-up and disciplined unit - although a lone model that pivots on the spot does count as moving for the purposes of shooting and so on.

On some occasions, notably when charging, a lone model has to perform a wheel (when charging, a lone model must follow the normal charge rules, which do not allow pivots, only one wheel whilst moving, and another to 'close the door'). In this case, wheel from one of the front corners as you would for other units."

So, you can pivot first in the direction you want and then move. However, you are not allowed to pivot first, before declaring a charge (unless specified otherwise, of course, like in the case of Random Movement). [Edit: In fact, Random Movers are not really an exception, since they do not actually declare charges.]

Note also BRB Official Update Version 1.9, p.9:

Q: Does pivoting on the spot count as movement for the purposes of units, other than war machines, with the Move or Fire rule?(p73)
A: Yes.

3. Unbreakable just means that Break tests are passed automatically.

BRB p. 129: "If the attacker wins, the defender must take a Break test."

Unbreakable units pass this test automatically. Hence, the attackers must kill every single model of the defending unit, before they can occupy the building.

"If the garrison doesn't flee the building, either because they've held the attacker to a draw or beaten them, or have lost the combat but passed their Break test, then the attacker must withdraw from the assault, and is nudged directly backward 1". The close combat ends, and the attacker must launch a new assault next turn if he wishes another attempt at driving the garrison out.

The assaulting unit does not have to take a Break test if the combat was lost. The warriors in the attacking unit know full well that the garrison cannot run them down if the combat goes poorly and automatically retreat in good order with no chance of a rout."

The Unstable special rule is dependent on having lost CC, not on having failed the Break test. Hence, an Unstable unit that has lost combat (attacker or defender), will suffer extra Wounds.