Based on Octavius's opening speech, what strategy had Antony predicted of Brutus and Cassius in Julius Caesar?

Octavius says that Antony predicted that the enemy would stay in the hills, but they didn’t.

After Brutus and Cassius assassinated Caesar, Antony forced them to leave town by stirring the people into an angry mob during his eulogy.  Antony and Octavius formed a triumvirate with Lepidus to rule Rome, but Brutus and Cassius were not satisfied.  They formed their own armies and came against the triumvirs.  Antony predicted that Brutus and Cassius would not...

Octavius says that Antony predicted that the enemy would stay in the hills, but they didn’t.

After Brutus and Cassius assassinated Caesar, Antony forced them to leave town by stirring the people into an angry mob during his eulogy.  Antony and Octavius formed a triumvirate with Lepidus to rule Rome, but Brutus and Cassius were not satisfied.  They formed their own armies and came against the triumvirs.  Antony predicted that Brutus and Cassius would not come to Philippi.  As Octavius points out, he was wrong.

Now, Antony, our hopes are answered:
You said the enemy would not come down,
But keep the hills and upper regions;
It proves not so: their battles are at hand;
They mean to warn us at Philippi here,
Answering before we do demand of them. (Act 5, Scene 1)

Antony had a reason for believing they would not come.  Philippi was a strategic disaster for Brutus and Cassius.  They did not have the battle advantage.  Cassius did not approve of the plan, but as usual Brutus overruled him.  This was decidedly a bad idea because Cassius had much less experience than Brutus.

Like Brutus and Cassius, Antony and Octavius disagree.  Antony feels that he knows better because he is older than Octavius and has more military experience.  When Octavius points out that Brutus and Cassius are meeting them in battle, he says that they are just posturing.

Tut, I am in their bosoms, and I know
Wherefore they do it: they could be content
To visit other places; and come down
With fearful bravery, thinking by this face
To fasten in our thoughts that they have courage;
But 'tis not so. (Act 5, Scene 1)

Antony does not feel that Brutus and Cassius are actually brave.  He thinks that they are just showing off to convince Antony and Octavius that they know what they are doing and are confident in winning the battle.  In fact, they are in real trouble.

The four men are about to meet in parley, which is a battlefield conversation.  Antony and Octavius should present a united front, but that is not easy for them to do.  Their alliance is one of necessity, not friendship.  Both are ambitious and arrogant, and each one is ready to get rid of the other at the first convenience.