1. I don't believe LE stated that they saw her and her 'friend' go their separate ways. If they saw that, we'd have seen that too. After all, they purportedly released the last bit of footage that they have of her on camera. IIRC, LE stated that that is what the 'friend' reported to them and that they have no reason to doubt his account at this time.
2. The BF's story isn't exactly adding up with the new revelations that she reached him on the phone and was coming home to get the dog. One reason is that if she wasn't home in the hour or so it took her to drive to Ft Worth, he would've noticed then - not two days or more later - that something was amiss. If she indeed reached him by phone, he had plenty of time to convince her to sit in her car and wait for him to come get her. Then, he had 2-4 days to cover his tracks.
These are both hypotheticals of course, and I'm not accusing either of them. I'm just pointing out discrepancies and possible scenarios given the context.