Well, I'll tell you why I think they need attorneys. Tim Miller of TES has an attorney. He's not a criminal. I have an attorney and a list of other attorneys I have used in the past for specific problems. I'm not a criminal. My employer has a full-time attorney on staff. Attorneys provide legal advice not just on criminal matters, but on processes: how to get a divorce, buy property, negotiate contracts, behave in a traffic court hearing, process an estate after someone dies. Attorneys point out where ordinary people might run afoul of the law and not know it and where the government or a big corporation might be trampling on the rights of ordinary citizens. Attorneys mediate between their clients and other people, between their clients and government agencies (including LE), between spouses, between siblings, between their clients and employers, and so on. They draw up contracts and interpret documents so that clients don't sign away their rights. They give advice about the possible consequences of various courses of action. They teach clients how to present themselves in some of the most important public appearances in their lives. They file suits when clients have been damaged by individuals, governments and corporations.
Ron needs an attorney because as a parent he was/is a natural subject of investigation in a child's disappearance and even people who are fully cooperating with LE should have an attorney present. It is, after all, legal for LE officers to lie to people they consider suspects, to use deception, and to hold suspects for long periods of time without food, water and sleep. An attorney prevents innocent people from saying or doing things under duress that later can be used to convict the innocent. (See John Grisham's non-fiction book, The Innocent Man, for example.) He needs an attorney because he needs to appear on national television to keep his daughter's case in the news and thus needs advice on what to say to avoid (for example) violating the rights of others or hindering the investigation. (We can see a good example of what people shouldn't say when we look at Misty pointing at Crystal's family. Note that her attorney quit when she gave the interview. Ron and his mother never accuse others; their careful language infuriates some people but it's necessary.) He needs an attorney to set up any entity for accepting donations or for setting up a foundation, as many families of the missing have done.
If you are interested in well-written true crime stories, a book called A Rip in Heaven, by Jeanine Cummins, details the rapes and murders of the author's cousins, who were forced to jump off a bridge into the Mississippi River. Their male cousin was held at gunpoint during the attack and forced to jump with them. He was the only survivor of the attack and became the initial suspect because he survived. It took a tremendous attorney to get him out of jail and eventually get LE to look for the killers, who were found and convicted once LE started to investigate what the cousin told them. Another great attorney handled the prosecution, giving the family some measure of justice for the lives of two young girls. Innocent people need attorneys, too, for all sorts of reasons.