Just curious as to whether you have ever litigated a class action as an attorney in the United States? Because named class representatives do testify at depositions and, if it goes as far as trial (which is rare) often testify at trial.
Courts don't "order" parties to give refunds (or pay money) unless there has been a trial and a finding of liability as determined by the fact finder (which is usually a jury the rare instances in which a class action goes to trial).
If a class action is filed, Tesla isn't going to voluntarily offer refunds. Assuming the case isn't relegated to arbitration, Tesla will defend the case in an effort to prevent class certification. If the class is certified, then that is when Tesla would most likely offer a settlement. At that point, ALL class members would be entitled to partake in the settlement according to the terms negotiated by the parties. In fact, all FSD purchasers who fell within the scope of the class action would automatically be included in the settlement (unless they specifically opted out of the class by the specified date).
None of this would be included in a class action settlement. The class settlement would most likely be for a dollar figure equivalent to a refund (perhaps, but not definitively, provided in the form of a coupon towards a future FSD purchase).
Again, I don't know if you have actually litigated class actions as an attorney in the United States. (Based on the misinformation in your posts, I am inclined to believe you have not.) However, regardless, the process as I have described it, is representative (pun unintended) of the manner in which class actions work.