I have no idea why you would get the idea that Banquo does not want to put out a candle. He is only in two scenes where he is in the dark: Act II Scene 1 and Act III Scene 3. In the latter he carries a torch which he drops when he is attacked. In the former he and his son are talking about how dark the night is: the moon is down and the stars (nights' candles) are not visible. But there is nothing which would suggest that he is carrying a candle. Some directors might put it in, but it is not in the script.
Assuming you meant when Macbeth sends the two assassins to murder Banquo and Fleance, it is because he doesn't want Banquo's children to become kings like the witches predicted. It only worked half way, because yes they did kill Banquo, but not Fleance.
Lady Macbeth wasn't in on her husband's plans to kill Banquo. When she asked what his plans 'of dreadful note' [Act 3 Scene 2 Line 44] were, he didn't want her to know the specifics. But most likely yes, she would have wanted Macbeth to kill Banquo. Earlier in their conversation, she commented that Banquo and his son Fleance were mortal [and therefore killable?].
Banquo wants to discuss the witches' prophecies with Macbeth and their potential significance. He also wants to share his suspicions about Macbeth's recent actions to see if he can uncover any truth behind Macbeth's sudden rise to power.
Murder someone. Specifically. Banquo and Fleance.
To make sure that Banquo's son wont become king as the witches prediccted.
Macbeth killed Duncan because the witches predicted that he would be the king but at the time Duncan was the king so in order to be king Macbeth kills Duncan since he was the successor at the time.
He feels guilty abouthaving Banquo killled- apex
In Macbeth's mind there is no justification for killing Duncan. He didn't really want to do it ("We shall proceed no further in this business") and regrets it the moment it is done. In the case of Banquo, however, his reasoning has been blunted by his fear and paranoia ("My fears in Banquo stick deep."). His fear of Banquo is unfounded, but in Macbeth's mind it does provide a justification of sorts.
( Be innocent of the knowledge, dearest chuck,/ till thou applaud the dead.) from apex
because they both have the same friend and he don't want to upset them and it wont be suspicious
Macbeth fears Banquo's noble nature, wisdom, and valor.Plus, if the rest of the witches' prophecy comes true, Macbeth notes he will have sold his soul to the devil (by killing Duncan) for Banquo's kids to take his crown.
Macbeth wants to know wether or not fleance is going riding with his father in the afternoon before the banquet because if they are riding together it will be easier for the murderers to kill both of them and "kill two birds with one stone."