[I cannot give you character analyses for all four of these due to eNotes rules.]
Banquo is portrayed as a virtuous person, courageous and proven in battle
They smack of honor both.
He seems genuinely pleased for Macbeth when the witches proclaim that he will be king.
..Things that do sound so fair...
He is keen to hear about his own future and a little confused that his sons but not himself will be kings
Thou shalt get kings thou thou be none.
There is some controversy around the part he played in Macbeth's fulfillment of the witches prophesies and his inaction
'oftentimes, to win us to our harm,
The instruments of darkness tell us truths,
Win us with honest trifles, to betray [us]
His perception of the situation and understanding of the witches' agenda should have then spurred him to prevent Macbeth from causing the tragedy which would include his own death. Thus his character is flawed.