No. Her arrest is not imminent, IMO.
Why?
Because the DA doesn't have enough evidence yet to tie TMH to Kyron's disappearance. And until or unless they are able to ascertain whether Kyron is alive or not, what exactly would they charge her with? Suspicion isn't enough. Gotta have proof to show a crime was committed, the person committed the crime, and evidence to link the person to the crime. And all of that has to be provable to a jury beyond a reasonable doubt before any DA is going to agree to an arrest.
Unless someone who has info spills what they know, or TMH confesses, and/or LE gets some corroborating evidence, or they find Kyron, I doubt there will be an arrest anytime soon.