What strikes me, having read the posts on here and on FB, is that there is little focus on what Corrie did in the evening BEFORE he left Flex and went into the Horseshoe. I think there was a brief mention of his going to 2 pubs and then Flex. Someone local who was in those places may know who he mixed with there. Maybe someone he met in the pubs or Flex, or even on the way to those places, offered him a lift or a hook up (maybe CCTV will show him speaking to strangers earlier in the evening). Maybe someone who he mixed with during the evening is the driver of one of the cars being investigated.
We've touched on the idea that he may have arranged something while out in the evening, but if we work on the assumption the phone was separated from him (which suggests unwillingly) you're kind of accepting this is premeditated and planned opposed to the work of an opportunist. This is obviously just my opinion.
I don't think the photo message is relevant. It appeared the family knew who it was sent to and why.