I think you are quite right on, CountessKate. There is strong evidence that Maria Amalia loved her mother, despite their differences and her refusal to be dictated upon.
I also think Maria Amalia's hostility to Du Tillot was also because he slandered her at the foreign courts (according to a reliable source on Piacenza's history); it's likely that she did view him as someone who should serve her and her husband, instead of making things difficult for them. It wasn't as if she was prejudiced against commoners as there is evidence that she was more disposed to the commoners rather than the nobles.
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Joseph II on Maria Amalia and his other siblings in a letter to the Comte de Provence in 1786 (my own loose translation):
"My friend,
For the discontent, which often finds itself exposed to a monarch, I seek the peace and domestic joys that robbed us of the throne, in the circle of my family.
My brothers are so dear to me, and my sisters.... since I lost the joys of fatherhood, they have become my replacement for everything that I was robbed of fate.
The Grand Duke of Florence is a prince, the patriarchal virtues, has his home and father of his people at the same time, he is loved by everyone, Tuscany is the happiest country in Italy.
Archduke Ferdinand, governor-general of Milan, connects with the character of the German princes, the finest qualities of our late father, kind, benevolent and condescending towards the people for his friends.
The elector, my youngest brother is born to be rulers. I have the most tender friendship for these princes, and the land which he confided by Providence to lead, would complain if the dictator usurped Germany would have prevented his elevation.
Such are imperfect features from the paintings of my family, I am too much the friend of these gentlemen, but that my heart could still be in the description of their characters,
From the circle of men, I hasten to make you an outline of the princesses, my sisters.
The oldest, Maria Anna, is pious, virtuous and kind, a lady of higher human species, created for the joys of another world.
Christine, Governess General in the Austrian Netherlands and the wife of the Duke of Saxe Teschen, my second sister, a fine woman. The joys of motherhood would glorify her lot in life.
The Archduchess Elisabeth is a very amiable lady.
The Duchess of Parma (Maria Amalia) and the Queen of the Two Sicilies (Maria Carolina) are Amazons, if I may use an an allegory. Two ladies who have made their nation worthy of confidence and (with) talent enough to govern men and empires.
Antoinette, the queen of the Franks and the wife of Louis XVI. Her charms captivate two nations. She is revered by the people of the Gauls, loved and admired by her husband and of Europe.
You see, my friend, in this picture, is the source of my joy. See in this, what are my compensation for the injuries which gives the diadem, and if approved would be the envy of morality, you envy me because of the happiness that my famiy provides, and what with the dearest gift of Providence.
Joseph"
(I think it was unlikely that Joseph was wholly unaware of Marie Antoinette's reputation and her unpopularity in France by 1786 for it definitely started earlier. The only thing I can think of is affection for his sister regarding his flattering words on her).