Only follow your representative's advice, not mine. But I'll focus on general points and psychology:
If your claim is sound, the respondent will most likely want to settle at the phone conciliation. I've had some experience of phone conciliation, but not in the FWC. However in that instance it was as you describe: You state your case, they reply, the arbitrator then speaks to the parties separately and attempts to negotiate an agreed deal.
I know you are angry about what happened to you. I am angry on your behalf as well! But keep your cool in the phone conference. It's not going to help get what you want. You only have one of two goals: Your job or dollars. Keep your focus on the prize.
Decide before hand on the lowest amount you are prepared to accept unless you want your job back. If you want your job back you know what your goal is. This amount needs to consider whether you are prepared for the financial and emotional costs of going to court or the FWC again. I would ask myself this: If I settle for a reasonably low amount at the phone conciliation, will I wake up in ten years time wishing I had nailed the sh*ts to the wall at the Federal Circuit Court instead, or will I wake up in ten years time thinking I did well that day, I proved them wrong, I was compensated and I moved on to better things. As I said in my post above, there are other opportunities for conciliation with the advantage that you and the respondent will already know the amounts both sides were prepared to accept.
Basically, their lawyers are thinking "is it going to cost my client more in legal fees at court than to just pay the applicant what they want"? Remember, even if they won at the Federal Circuit Court or FWC, they still couldn't charge you for their costs unless your case had zero chance of success. Do you have an okay case? If yes, no judge is going to make you pay their costs if you lost.
Read up now on how any potential payout will be taxed. Why? Because there are lawful ways a settlement for damages is going to pay less tax than if you'd earned the money in the first place. You want to make sure as much as you can that your negotiated agreement is for an amount that is going to require the least amount of tax to be paid. Be proactive about this. Don't leave it up to their lawyer to unilaterally decide what they are going to tell the Tax Office.
Remember to include an amount for superannuation as well as annual leave etc when you're deciding on your minimum acceptable amount.
Have it agreed in any settlement, if you can, that your employer will give you a good written work reference and will agree to give good phone references. Have it specified in contract which senior employees are allowed to give out references. I don't mean it has to be your best buddy, I mean it puts a legal onus on the agreed senior employees to give you that good reference or risk you suing them for breach of contract. Having guaranteed good references from your employer is one of the major bonuses of legally binding settlements.
