I dislike
Addison and
Emerson on girls, mostly because of the -son ending. Also the names will be extremely datable and I don't think they are that uncommon, I think once the stats come out for this past year we will see them on the list.
Addie is an alright nickanme if a bit young sounding. I would much prefer to see it as a nickname for
Adelaide,
Adelle,
Adeline /
Adelina /
Adelita,
Adora, Adorina or something other than
Addison.
There are also so many full name possibilities for the nicknames you listed for
Emerson. Hypothetically, if you did use Emerson...using
Emery wuld only make it seem more masculine, seeing as it is a male name.
Grace is also highly overused as a middle name. It' s a nice name, and it sounds good with many things which is why it is so popular.
If I could swing it with a husband I would definatly use
Emerson or
Addison for a son. Also, before you ask I would also use
Madison and most other unisex names.