Can't add to the badges , I've only got :
1. Sharp cornered brass (J.R Gaunt & Son).
2. Rounded cornered brass (J.A Wylie & Co).
Regarding the Firth backplate , I've no idea about the who/why of its awarding.
If it is connected to the certificates then 'possibly' given to those who worked at the factory for the full duration women were employed there (dates on both certificates the same).
The 'hierarchy' doesn't seem to apply as one was a 'ganger' and the other simply a worker.
Found an interesting dissertation about the lives of munitions factory workers.
Women’s Work in Munitions Factories during The First
World War: Gender, Class and Public Opinion.