There may not be any secret strategic reason behind the timing of the child *advertiser censored* charges. <snipped>
So I'm probably trying to read too much into too little data here, but if option #2 is what LE are going with, maybe the child *advertiser censored* charges are a way of convincing McDaniel to give up any lingering hope of just a life sentence. With seven charges of child *advertiser censored*, if the sentences are not concurrently imposed, then McDaniel gets a minimum sentence of 35 years in prison, likely more. Already, the potential 30 years are off the table. If McDaniel's shot at a life sentence can be eroded down to nothing, then his options are down to two: life without parole, or death penalty.
I still think the plan is to go for the death penalty, though. In which case, the real reason behind the child *advertiser censored* charges is probably just, "Why not?" Keep throwing stuff at McDaniel, and eventually he will lose any chance of the jury viewing him as an awkward kid that somehow got in way over his head, of someone who made horrible choices, but, prior to this point in his life, was otherwise normal. Instead, the LE can show McDaniel is basically a rabid dog. And there's only one thing you can do with those.