Sigh. Quit worrying about it. What is done is done. I have already told you that if they said poor performance, they can't come in at the hearing and say they fired you for tardiness or having a bad attitude or stealing money from the office coffee kitty. If they try, they will be told that the only relevant information is the information they can provide about your alleged poor performance.
As we said, OF COURSE they are going to object to your drawing benefits. It doesn't make a spit of difference whether the supervisor said or didn't say they would fight the claim. Of course the company is not going to voluntarily let someone they have terminated for poor performance draw benefits without objections. If they had had no objection to your drawing benefits, they'd have let you go due to lack of work, and that would've gotten you an automatic approval.
But incidentally, even if your employer does not appeal, you have to show up and answer and convince the unemployment service that you did not deliberately screw up on the job. If they decided your poor performance was deliberate, they could not approve your claim even if your employer "didn't fight it." Your boss didn't know diddly about unemployment benefits, it sounds to me like, and you blindly trustingly asked if you could have it, and they made up something and told you that would make it sound like HR was the "bad guy" and not your supervisor. But as you've repeatedly been told, it doesn't matter.
You no longer work for this company. What he said and she said and they all said, and then I said.....is past. Now why don't you quit overthinking this issue and move on toward finding another job. Please. You have been reassured, it has all been explained to you. So read what has been said everywhere and find another activity to occupy your mind between now and the time of your hearing. If you are not approved, appeal. Then let's see what happens.