I would not feed IAMS. Read some other posts on here for some ideas re better quality kibbles. Among other things, you want the first ingredient to be a protein, not ground yellow corn, which is often the case with a low qual kibble.
I would delay picking your pup up until 8 weeks. At 6 weeks they start learning bit inhibition from their littermates. If the pup goes home earlier, he/she might not realize this is a no-no and you'll need to teach it. My girl was adopted through rescue, but I spoke to her original owners who took her home at 6 weeks. She does not have good bite inhibition and this is not good. I do not have young kids now, but when I do, I'm not sure how I will handle it. It is difficult to correct this problem (for me) b/c it does not rear it's head frequently.