Charlotte is the twin sister of the devious, Emily LaGuerre (GCXTCT). She also has the same mother as Purr LaGuerre (GCR2F3) and Chelsea LaGuerre (GCR9RR) although she and her sister are from a later breeding. Charlotte is known as "The Good Twin" and is horrified when people confuse her with her sister Emily, "The Evil Twin."
All the other cats in her family have created caches so Charlotte decided it was her turn to place her own. She is not as math literate as Purr, nor as artistically talented as Chelsea, nor as duplicitous as Emily, so she decided to put out a simple puzzle cache close to the series placed by her siblings.
Knowing that as a twin, she would be confused with Emily, Charlotte wanted geocachers to note her subtle differences. To help them out, she has provided the series of pictures below. Each line shows 4 pictures of Emily and one of Charlotte. Find Charlotte and she will provide you with a digit for the final coordinate.
The final cache is at:
N 42° 19. ABC
W 71° 17. DEF
Can you distinguish Charlotte from her twin?



Note: All seven of the cats wanted to be close to each other so we placed Purr LaGuerre, Chelsea LaGuerre, Emily LaGuerre Too, Charlotte LaGuerre, Boo LaGuerre, Ghost LaGuerre, and Goblin LaGuerre in the same town and not too far from each other.

You can validate your puzzle solution with certitude.