As I looked at other known photos of the girls, I began to suspect that the correct order for the trio was Emma, Annie, and Minnie.
I am going to assume that we have correct birth and death dates for Anna and Minnie. Anna was born in 1877 and died in 1918. Minnie was born in 1880 and died in 1895.
Emma is the real mystery woman here. The 1870 census places her birth in 1859, the 1880 census says 1861, and the 18890 census puts it in 1860. The census actually lists an age rather than a birth year so depending on what month she was born in and what month the census taker visited, you can be off by a year and still have a match. Lets just say that the combined census data is claiming that she was born in 1860.
If Emma was born in 1860 she would be 17 years older than her sister Anna. Have another look at the photo. Do any of these girls look to be 17 years apart in age?
Another question - Is this Emma's wedding photo or was it taken at a different time? The only thing I see that could be a wedding indication is the flowers on Andrew's lapel.
This one isn't going to be easy to sort out.
Now that Emma's birthday wasn't the mystery, my focus shifted to figuring out who the girls in the photo were.
The first thing I considered is that one reason I was so sure the center girl was Anna, was because she had dark hair. I began to think this might be a mistake. When I was a child I had blonde hair. When I was in my early teens it was a dirty blonde or light brown. It kept getting darker and by my mid 40s had turned into dark brown. If Anna was one of the younger girls in the photo she might have still had lighter hair.
At this point my son, who is 27 years old, looked at the photo and told me that he thought the girl in the center was much older than I did. He said "she is at least as old as me, if not older." Taking a good look at him I began to realize he is right. I've reached a point in life where I think just about everyone younger than me, looks very young. I go out to eat and I can't believe the kids serving me are old enough to be serving beer. I think they look like they should be in high school yet. Obviously I've gone from being bad at guessing ages to a new, more embarrassing level of failure.
There was also a slight problem with the noses in my last theory. This new theory corrects that.
So let's look at all the photos again. Remember the one where Mr. Erickson had a flower on his lapel? Let's assume that was their wedding photo and Emma was 34 years old at the time. Let's also assume that the girls in the photo are about 30, 13, and 10.