Marie Valerie and her sister Gisela are two of my favourite archduchesses, after Empress Maria Theresa's daughters.
It's fascinating that there are letters preserved from her governess.
This is what I know of her life:
She was raised by her mother, who insisted that Marie Valerie become the family's "Hungarian" child, and her first language was to be Hungarian. She was very shy as a child and this spelled "trouble" for her as she was deemed as distant and haughty, and certain ladies at court disliked the fact that she was a "Hungarian" child.
When she was born, her father Franz Josef wrote her siblings (who were in Vienna) about MV's birth, saying she had remarkable blue eyes, was a beautiful child and very strong. Rudolf and Gisela's reaction was to resent the "fuss" made over, in their view, the "outsider" (Rudolf & Gisela were very close, and almost a "separate unit" within their little family).
It was rumored (rubbish, of course) that MV was not the child of Franz Josef but of Empress Elisabeth's "favourite", a thing that quite bothered the young MV (who hated the guy in question). When she was finally allowed to speak German with her father, she was overjoyed. MV accompanied her mother in her travels.
Her brother Rudolf wasn't always very nice to her (because of jealousy; he wanted their mother's attention but it seemed that Sisi only had attention for her youngest) but she had a nice relationship with her older sister Gisela as adults. Rudolf & Gsiela bonded with each other even more after the "fuss" shown over MV. Fortunately, both girls inherited their father's calm character, very even tempered, unlike their mother and brother. MV was only 4 or 5 years old when Gisela married and moved to Munich but it seems that they had a great and close relationship later on.
I remember reading that MV, as a teenager, was very unhappy one Christmas because of Rudolf's "poor" treatment of her. I think this was the time when she wanted to marry their (penniless) distant cousin but Rudolf was very much against the match. Her father also thought a match with the Crown Prince of Portugal or Saxony was a much better prospect for his daughter but in the end, her mother supported her so she was allowed to marry her cousin.
As 19th-20th century royal, she didn't hold a job or any duties except to be present at court events. It's likely that MV, as an adult, was a big help to her father in that respect since Empress Sisi disliked such socials and was always traveling. But when she got married, she seemed to prefer to live quietly in her country home, far away from court. It seems that she didn't like the "atmosphere" at court. But she was a great comfort to her father FJ later on, who visited her often (although she tried to interfere in his relationship with the actress Katharina Schratt).
Ms. Shelley, as for your great-great grandmother getting a job as Valerie's governess, I'm guessing Empress Sisi picked someone of her own liking. She really disliked the governess of her older children. I also presume your great-great grandmother was from a noble family... royal governesses back then are always from the nobility. The head of Gisela and Rudolf's nursery was a countess, aided by a sub-"aja", a baroness. "Aja" is the term of the Habsburgs for their governesses and has Spanish roots (although they may have personal nicknames for them, I understand Rudolf's aja the baroness was called "Wowo" by him). As for her "uniform", I'm not very familiar with 19th century fashions but surely she dressed as the court protocol demanded.
A royal governess' duties (and ladies in waiting) included making sure the children ate properly, said their prayers, washed regularly, dressing them, teaching manners, being the child's first "teacher", admonishing them (or in some cases, spoiling them), among others. At age 5 or 6, they left leave the nursery and perhaps turned over to another person (a governor for the princes) or sometimes, in case of females, had the same governess (case to case basis).
I only have 1 book on that generation of Habsburgs, specifically on her father Franz Josef, but MV is mentioned every now and then so I'll look it up and post here.
I've got a couple of pictures of MV as a baby and a toddler. Do send me a PM (with your email address) if you wish to have them as I don't know how to post pictures here, LOL.
Finally, here is the link to another forum which has a thread that discusses the ladies in waiting, nannies, chamberlains, etc. of the Habsburgs. It seems that the only info/pictures posted are those from the time of Empress Sisi, which should interest you, Ms Shelley: