I am getting to keg a sour that was brewed last september. My question is related to the equipment. After I tap this, should I buy new o-rings, dispensing line, etc due to the yeast so that I don't infect a regular batch with the Brett?
Save your money. Just pull everything off if you're concerned and just drop it in a pot of boiling water for 20 minutes. This is what I do to my fermentors to prevent cross contamination. I boil all the rubber and posts as well as the gas tube. The liquid tube just gets flamed with a torch because it's too long to fit in a boil pot easily.
Going through life is hard.
Going through life stupid is harder.