i think abhi chose to take riddhima in this project because he wants to prove who has the power, after all he is their boss. Armaan fought for nikita as he didnt want her to be a part of this project but he lost. Abhimanyu probably chose riddhima to prove a point to armaan (that he is the boss, he can make riddhima work for him n armaan cant do anything about it as he lost the match).
i dont think abhi wud stoop low n appoint a girl for the entertainment of patil. he even said it to patil on the fone that the presentation is important n not whether riddhima comes or not.
just my opinions. 😊