HRTO mediation - what should I ask a paralegal before hiring them?

I just got my HRTO mediation date and I’m looking for representation. Couple questions:

Is mediation mostly negotiating a settlement, or are you actually arguing your evidence?

What questions should I ask before hiring someone?

Is contingency normal for HRTO cases, or do most people pay flat fee for mediation?

Anything you wish you knew before mediation?

Would appreciate hearing from anyone who’s gone through an HRTO mediation or represents applicants. Thanks!