I'm not sure how to determine where the green sunfish came from. I want the pond to be a fun way to put meat in the freezer. The channel catfish will be pellet fed. Will they still compete woven the bass?
Yes they will compete with the bass for live food once they reach around 3#. If you stock the CC, don't release ANY back into the pond because they will become VERY hook shy quickly and teach the other CC in the pond. The bass you caught were probably around 15" - 16". If so, then if you were to put any BG in there they should be 6" or bigger to minimize the LMB from eating them. If you are stocking 1# CC, they should be around 14" or so which is eating size.
I'd start chucking the GSF out of the pond when caught, because they will compete directly with the LMB for food. A GSF will eat the same sized food that a LMB up to around 7"-8" will eat.
You are on the right track, I'd just adjust the size of the BG that you are going to stock, and remember to harvest the CC when caught. If you like eating them, then stock 100 since you will be pellet feeding them. Just don't release ANY back into the pond once caught.
I would remove 20-30 pounds of LMB this year to eat, and then keep removing 20 pounds per year after that. If the LMB aren't putting on a pound of weight per year then I'd remove 30 pounds of LMB of all different sizes when you see them not adding the weight. Like Dave Davidson said, too many cows in a pasture will slow down their growth, LMB are no different. VERY few LMB will feed train themselves.
I would feed either Endurance Feed, Triton Feed or Purina Aquamax or Sportfish Feed. Don't feed the cheap feed store brand fish foods, you will not see the growth and while at first the cheap feed seems to be the cheapest to feed, in terms of pounds of fish grown vs. pounds of feed thrown, those feeds that I mentioned are actually cheaper to feed. You can feed the cheap catfish food which the catfish will grow on but the BG and any LMB that eat it won't. Or you can feed the stuff I mentioned, and the CC will grow faster, and the BG and LMLB will also grow.