There is evidence that LE is looking for forensic evidence, which is why I believe they don't think she's still alive. Besides the car, soil samples and gas cans, I believe they have been focusing on the area around the GP's home. My guess is that the helicopter was indeed looking for forensic evidence in the area, possibly due to information obtained from her E-pass records and any traffic cameras in the area. I don't think LE has ever thought that this baby is still alive.
Last night I did some digging around on DBC Entertainment after seeing Tony and some of the other guys wearing DBC shirts at Fusian. Besides being a "film" company, there is what looks like to be another company that hires live entertainment and bands for Fusian's weekend promotions. It looks like many of these kids Casey was hanging around with worked with this company in some capacity. Is there a relation of some other kind to Fusian? Maybe.
As Truly has uncovered, the Fusian holdings are complicated. I'm not willing to speculate but it is interesting and it is info that I think is worth looking at or, at the very least, filing away for future use. If this was any other case, I would say it's a farfetched theory but there is nothing textbook about this case. In fact, I'd say this is a case where the truth is definitely stranger than fiction. And I say that tongue-in-cheek, as there doesn't appear to be much truth to find.