I’m not expert for aerodynamic, just like most people here. But such stuff see many times. Hot air from front brakes probably can not affect so much engine cooling, and engineers probably make some fins inside to disperse hot air or to direct them upward or downward, not directly in engine.
So, two passenger must use legs or public transport now? Well, be in back seat in such beasts is not pleasure, as far I know. Silhouette is very nice, do you plan back spoiler. Maybe some which can retract in body. This is not necessary, and can ruin silhouette , but many people love to see this.