No.
Double no. Just look at all of the AR-15 shooters in NRA Highpower. The gold standard brass is Lake City surplus. (Holds more powder than commercial brass.)
Absolutely yes. Although I think any good Hollow Point or Hollow-Point Boattail bullet is capable of being "Match Grade."
Match grade ammunition is ammunition that will hold the X-ring from 200-600 yards. My experience is that good (consistent) bullets and powder mean far more than what I do to the cases for accuracy (within reason).
I am content to have my 600 yard ammo sorted by headstamp only, throw powder instead of weighing it. The only stickler I have on this ammo is seating depth. As long as that is on, I am happy. Not cleaning 600-yard targets is due to the shooter, not the ammo with my current equipment.
Short-line ammunition has to plentiful. Loaded with good powder and bullets, the big point here is simply having enough to practice with to get good at keeping them in the X-ring. I think any true match-grade bullet will hold the X-ring of an NRA Highpower target from 300-yards with a powder type and charge that makes the barrel happy.
Other than that, it is more important to get out and shoot in my game (Highpower). If I were a benchrester, my answers would be completely different.