Are there any context clues in either the book or the show to support Cersei choosing the Mountain for the trial by combat in having hopes or the foresight to know that Oberyn would choose to fight him and thus affording her with the opportunity to kill both Tyrion and an enemy of the family in one single act?
The Mountain was chosen to fight before anyone had volunteered for Tyrion and because he is the a ruthless and effective killer. Cersei's main goal is to see Tyrion dead for the murder of Joffrey. She wants the Mountain to fight and win the trial by combat ensuring Tyrion dies. Who he kills in the process did not matter. If anything Oberyn saw the trial as an opportunity to kill the Mountain and avenge his sister rather than the other way around. It likely came as a surprise to all the Lannisters after they had tried to court him.
I no longer have copies of the books or I would find quotes but there are a couple scenes from the show that support this. These scenes contain spoilers from season 4.
Cersie does not care who the Mountain fights.
Cersie believes she has swayed Oberyn to her side.
Tywin (and by extension the Lannisters) needs Oberyn on his side.
Cersei was going to pick the Mountain regardless. Gregor is probably the most dangerous fighter in single combat around, and Cersei had no real incentive to pick anyone that Tyrion could conceivably beat. It would have been an embarassment for her champion to lose the trial so it is only natural she would pick the strongest available fighter. Oberyn was just an unexpected bonus.
She wanted the Mountain to fight against Tyrion's champion because he's the most powerful warrior, and she thought Tyrion's champ was going to be Bronn, because he always fought for him.
So she picked a warrior who certainly could beat Bronn, and even better, Bronn knew that, so he wasn't going to fight (because he was a mercenary and the honor is not a priority for him). Even if someone else thought to fight for Tyrion, when they saw the opponent they rejected that idea instantly.