Absolutely. Some people believe only low-conflict situations are appropriate. This is not true. In fact it is high-conflict disputes that really need mediation. Mediators are experts in conflict and should be able to help people get through the conflict to be able to make better decisions and lasting agreements. Attorneys are experts in legal matters. Accountants are experts in financial matters. Going to an expert in dispute resolution really makes sense for people who are not used to working collaboratively.
You are welcome to bring any expert or support person you wish to mediation. There are many people who may be of great help. Lawyers, accountants, realtors, etc. may all bring useful information to help you make informed decisions. Both/all parties should agree ahead of time who will be present. Sometimes it helps to have the first mediation session include only the parties directly involved in the conflict. Experts can always be called on for information or to be included in a later session.
Getting divorced is a legal process with certain requirements set up by each county government. You may certainly hire an attorney however there are other options. Once you have an outline for your agreement a paralegal can be hired to fill out the forms for your particular county. There are also respected online services which walk you through the process for your particular state and fill in the agreements you and your spouse have made.
While open communication (via the First Amendment, no less) guarantees that people may say what they want, it does not ensure that all points of view will be heard, that they will be listened to in ways that promote common interests, or that there will be an appropriate response to what is said. Mediation will help in a variety of ways, but its biggest influence may truly be that participants will have an opportunity to experience not just open, but also effective communication.