All parties to a lawsuit would want to be named to the lawsuit, which would appear to mean both you and your spouse. All parties will need to appear. Testimony can come in through one or both plaintiffs.
You will be allowed to introduce evidence that is relevant and that you can properly authenticate. Small claims courts are usually somewhat relaxed in terms of how the rules of evidence are applied.
You would need to effect proper service on the defendant(s). We don't know the relationship between the broker and LLC, or if you would be intending to sue both the broker and the LLC. If you're suing both, then follow your state's rules of civil procedure for serving both - for small claims court, often a court officer will effect the service, so you should check local practices.
Odds are if you sue they're going to respond through a lawyer and move the case to a regular trial court.

