Ok, I'm a begginning knitter, so these might not be mistakes, but these are what I took for mistakes in the pattern and either changed or omitted:
For the round right after you finish the ribbing it says to *k2tog, yo* till one stitch remains - should say till two stitches remain.
Instead of placing the red and blue markers after the 20th and 60th stitches, I placed them on the 20th and 60th stitches.
For the back flap (when working in rows) I found that you need to repeat row 1 and 2 one more time (it says not to for the preemie size). If you don't repeat it one more time then you don't end up with 22 stitches in the end.
Then the second set of rows for the back flap are in reverse. Row 1 should be row 2 and row 2 should be row 1.
Then in the appendix when you are doing the kitchener stitch, I omitted the paragraph that starts with "set up" because it contradicts the following paragraph and the following paragraph is the one that made sense.
Hope that all made sense and that it was alright to post this here. It really is a great pattern though. If it weren't for all the details and pictures I never would have figured it out.