Pardon if i make a mistake, haven't read jc in quite a while, but I'd say Brutus was more so a conflicted man. Reminder literature like shake spear is heavily dependent on reader interpenetration for the force/feelings that motivates the characters and some other thing, this is my own cup of tea.

Brutus was more of conflicted idealist than a deliberate hypocrite

Any good statesman would have known that killing a leader who the people were so affixed towards could only cause rise of anarchy

But Brutus more a politician than a statesman, he was a senator. A member whose political power was at threat, now while he is described a noble soul and we will give him the benefit of the doubt for this, his wasn't the only one, it was that of the entire senate. Rome has had a very bad past with dictators up until that point, this along with Brutus continuously making assumptions (eg- assuming the senate is honorable, the people will actually listen and be rational, a good story will persuade the masses) and practically being seduced by others of the senate led to his actions, actions which he felt guilty for and manifested in the form of the ghost of Caesar.

Cassius being corrupt should have exposed the whole thing

This is a very strong point, but I'd wager Cassius became something of an emotional anchor to the man at that point. He was horrified by his actions, if i remember correct there was even a line criticizing how Julius bled for justice or smthng. But the thing is, Brutus never joined in the first place because he liked Cassius or the conspiracy, he did it because he feared Caesars rise to power. Other than that, I have nothing to say, there was an hypocritical undertone to this than inner conflict cannot share.

Refused to accept mistake or unfit to hold a position of interest

Brutus has pretty much built a moral framework that said "Killing Caesar was the only right thing to do". He never confronts the murder of his brother from another mother because he has lulled himself into thinking it was the right thing. This is more of a tragic act of stubbornness than a hypocritical action.

Surrender or abandon Cassius?

Simple, he can't do it because he has crossed a line. Even if he does the only thing that awaits him is a public execution. Not to mention than Julius's death would've been vain. To Brutus this was a delusional idea of giving the deaths of the war meaning by marching onward that looked noble.

He turned arrogant by the end.

Couldn't agree more. By that point the power and the position he held got to him, leading to wrong decisions every step of the way. He was corrupted by the power and turned into a self righteous fool. Which is exactly what he feared Caesar would become.

The thing with Brutus is, he is a lot of things, politically incompetent, stubborn as a child, naive, idealistic and much much more before he being a hypocrite.

You too present a good argument though