Lennox is the toadying politician: he follows whoever is in power. If it's not Duncan, then it's Macbeth. Next it will be Malcolm. He'll follow him too, blindly.
Macduff is the loyal Scot. He sacrifices family for country and mourns both with equanimity. He is the hero of the play, and his courage to fight the tyrant Macbeth is long overdue.
So, where does that leave Ross? In the wholly tragic world of Macbeth, it is nearly impossible not to choose sides. Roman Polanski, in his 1971 film Macbeth, has Ross as the third murderer. He then has Ross escort the two murderers to their deaths. Polanski plays him as a villain, almost from the start: observe the look Banquo gives him as Macbeth is being crowned at Scone. Daggers. Macduff, likewise, rebukes him on the passage from Inverness: "No, cousin, I'm going to Fife." Ross replies, "Well, I will thither." If nothing else, Ross clearly does not align himself with the hero.
Ross brings the news, yes, but he also brings Macbeth's reign of terror along with it. He seems attracted to the smell of blood: sometimes he is behind its smell, as in Act I, when he tells Duncan his reports; sometimes he is ahead of the smell, as in Act IV, when he warns Lady Macduff to leave her castle. (She is slaughtered shortly after).
Polanski's depiction may be conspiracy theory, but it is rather suspicious that Ross always seems to be in the vicinity of carnage.
Most of what Ross does is to bring the news.
In Act 1, Scene 2, he tells Duncan about the progress of the war, about the traitor the Thane of Cawdor, and of the bravery and victories of Macbeth.
In Act 1, Scene, 3, he meets up with Macbeth, tells him how pleased with him the king is, and tells him that he is the new Thane of Cawdor.
In Act 2, Scene 4, he tells the Old Man what an awful night it just was (the night of Duncan's murder), how the King's horses went wild, and who is suspected of the murder.
In Act 4, Scene 2, he tries to explain Macduff's actions (he has left his family to go to England in order to help free Scotland from Macbeth's rule) to his very scared and irritated wife, Lady Macduff.
In Act 4, Scene 2, Ross has traveled to England and relates to Macduff the terrible news of the slaughter of his whole family by henchmen of Macbeth
Act 5, Scene 8, Ross delivers his last bit of news. He tells Siward that his young son has been killed.
So, it really doesn't matter what kind of person Ross is (although it should be assumed that he is an honest and true Scottish nobleman) because his character's purpose is to move the story along and fill in the blanks. He does those things very well.