If this is an unemployment hearing, then yes, there will be three parties represented, usually. This will be you, the employer or their selected representative, and the hearing officer. You could, if you so choose, be represented by an attorney, but do not take your husband with you. You do not need his testimony that he heard your boss say it was lack of work. You may say as part of your testimony that your husband was on the line or you were on speaker phone when you talked to your employer and he heard your employer clearly say you were let go for lack of work. If you bring your husband, he will probably have to sit outside, would be allowed in only to say, "Yes, I heard the phone call. They said lack of work" You present the registered letter you received that said you were let go for poor performance. You state that you had no prior warnings, etc.
The hearing will be a very formal structured process. You will both be sworn in, and it will be recorded. You will only allowed to speak at your assigned time. "Taking notes" is rather superfluous, as once you have your hearing, a decision will be made. If you lose this decision, your paperwork, the transcript of the whole hearing and all evidence presented goes to the board of review. But you will not be given another chance to state your case, so you can't carry your notes off to someone else and then sue them. You are going through the legal process with this hearing.
Do not go in with a written argument or letter or document that you try to submit. You may, of course, have talking points written on your hand for when you present your case, but mostly, you will present, then the employer will present their case, and there will be opportunity for you to question the employer, the employer to question you, and the hearing officer will ask any questions they feel may help them understand the circumstances better.
The hearing officer only wants to hear things related to your termination. You may as part of the reason you believe you were let go bring in that you have had several health issues that have required you to be out some of the time, and you feel this may be the reason that you have been singled out. But if you had medically approved absences, and you were very diligent when you were at work, no, poor performance is not misconduct. If you keep saying you always did the job to the best of your ability, and that you were not even aware that the employer was in any way finding your performance unacceptable, you should have a very good chance to be approved.
Unemployment insurance is all you can get. It isn't right it isn't fair that you can be treated this way, but unemployment is the only recourse you have.