Welcome aboard. You are going to have so much fun here. I'm sure more knowledgable poeple are going to jump in and answer your questions. I personally have never dealt with droopy ears, but I know they can be taped up.
If the poo gets stuck too often, you can perhaps trim the hair around the bum. I do that for my dogs all the time.
And as for the chart, try this:
Yorkshire Terrier - Yorkie Puppy Growth/Weight Chart - watch us grow