Macbeth Act 2

2.2 lines 22-50 : Act 2 Scene 2's opening dialogue with Lady M shows a change in attitude with Lady M right off the bat. Where before she seemed afraid of Macbeth's failure, she says she is now confident that the deed will be completed, however we also see that she is as jumpy and alarmed as Macbeth when the owl shrieks, or she hears any noise.
There is also a sense that she is more hardened to the act that Macbeth has done than he is, even though she admitted she could not have committed the murders because one of the sleeping men resembled her father, and Macbeth is supposed to be the war-hardened soldier. The mentioning of her not being able to murder the men sets an almost-realization for Lady M; Macbeth has done what Lady M was not able to do.
The choppy dialogue and line structure enduces a sense of urgency and near-panic for the two Macbeths. Macbeth's panic comes from his lack of ability to give prayer to the two men he thought he heard praying before the murders. In his mind he has destroyed the calm of peace and prayer as evidence when he says "'Macbeth doth murder sleep'-innocent sleep" (line 40). He knows he will no longer sleep soundly in his own bed, which is also forshadowing Lady M's eventual spiral into insanity later in the play.
2.3 lines 89-94 : Macbeth leaves the room where the murdered men lay, and starts to speak about death, and mortality. It seems he is not only talking about the death of the men he murdered, and the death of the bloodline that these men were the head of, but also of the death of himself. He says "All is but toys. Renown and grace is dead." (line 91), which brings to mind the fact that he used the king and other men as pawns in his game to become king, or also that he himself is a toy that is being used by Lady M as she is the one that is encouraging Macbeth to commit these murders. Renown and grace could be an allusion to his own honor or internal struggle that died when he committed the crimes.

Questions:
1. In 2.2, when the Macbeths hear the knocking on the door, could it be that the knocking they are hearing is mostly internal fabrications from guilt or panic of being caught?
2. Also in 2.2, when Lady Macbeth mentions she was not able to perform the murder because one of the men resembled her father, we see a sort of softer side, of maternal protection for a father figure in her eyes. How does that contradict with the past mentioning of her murdering her own child if she so swore it? Are the two lines echoing one another, or is it a coincidence that while she feels a protection for a father-like figure, she could so easily murder her own child?
3.All throught 2.2 and 2.3, we see Macbeth fighting this internal struggle with himself over the murders he commits. If he is supposedly a hardened war hero, why is he having such a hard time with these actions? Is it that he has a sense of attachment and loyalty to the now-dead king, or does his guilt potentially stem from him feeling that these are the actions that he must take? What I'm trying to ask is, is Macbeth the tragic character being played by his wife and having to do these things for the betterment of his line?