Very good questions posed here. I'm not sure of the complete details on this case other than what has been made available through media and NamUs. I'm certain this could have been a drug-related crime or something to do with gang-violence. Based on what I've read, he has to be from Ohio or somewhere close; especially if he was seen in Reynoldsburg, OH. I don't think they ever found the red car he was driving.
If he used a debit or credit card to make that transaction in Reynoldsburg, there has to be some kind of a footprint, especially considering the fact that most surveillance videos are timestamped. If he used cash, then there is no footprint and no chance of identifying him that way or depending how well the CTV monitors recorded video quality, no chance of knowing what he bought. But I believe he was seen there about a few days before his death.
I am trying to see if I can obtain records of this case from the PD in that area; however the unfortunate thing is that most PDs have non-disclosure agreements; which mean no one in the public can have access to the files until they close the case.
In any case, I hope to get to the bottom of this case soon.