In Kesubos 10b the Gemorah defines exactly what almanah in the Mishana is referring to:
מאי אלמנה אמר רב חנא בגדתאה אלמנה על שם מנה אלמנה מן האירוסין מאי איכא למימר איידי דהא קרי לה אלמנה הא נמי קרי לה אלמנה
What is an Almanah? Says Rav Chono from bagdad: Her name means she gets a Maneh. -This would apply to a widow that consumated her marrage (rashi)- but a widow who was betrothed and still a virgin surely she gets two maneh? since we have coined a term for a widow from full mariage as "almana" we also use this term for a widow from betrothal (even though the name one Maneh does not reflect her value as vrgin to receive two maneh in her Kesubah)
So really there are only two categories:
a virgin who receives 2 maneh which include a regular newlywed, a widow from betrothal, a Yevama from betrothal or a divorcee from betrothal.
a widow from full marriage nissuin receives 1 Maneh like her name almanah, a Yevama from nissuin, a divorcee from nissuin and any woman who is not a virgin.