I know I'm a dork but I'm a twin and have twins so I did a lot of reading when I was pregnant about this subject
Boy/Girl always fraternal
Identical always has same blood type
I forget the exact days but if the egg splits quickly they can have seperate sacs and still be identical
DNA is the only real way to tell. Although their DNA isn't exactly alike it is very similiar and are very few markers that are different.
Fingerprints are also similiar are far as the main ridges and loops but have some differences.
Fraternal twins are no more alike than a regular brother and sister born as different times.
I have known a few different sets of identical twins although identical they have all had different personalities. That may just be due to their environment though I don't know.
I am an opposite of my sister. she takes after my dad and i take after my mom. My kids are boy and girl so obviously fraternal. my boy has dark curly hair and green eyes like me but my girl has blonde hair and blue eyes like my husband. He's bigger than her and no one has believed they were twins since they were about 1 because he's so much bigger.