I like to imagine that Julia Bertram and Fanny will eventually become real friends

In the book Julia shows moments of almost-compassion and almost-kinship, after experiencing a few stings of rejection, marginalization, and jealousy, herself. There is (if I recall correctly) only one moment where she goes out on a limb and sticks up for Fanny. I somehow came away with the impression that, deep down, Julia could always tell right from wrong, and just from unjust better than Maria or Tom. It was implied in the text that Julia lacked the emotional depth and maturity necessary to empathize fully (at least with Fanny), as she is too wrapped up in herself and her own feelings. Fanny, however, often observed Julia with a kind of distant sympathy and care.

In my head cannon, after losing Maria for a while, falling in love with Yates, and becoming estranged from her other family - but then reconciling, and ultimately discovering them to have missed her, and each of them to have done a bit of soul searching themselves, I believe Julia could have had a major psychological growth spurt, realizing the importance of family and deeper connections. I like to imagine that in her 20s, she reflects more on Fanny (as well as Edmund), and recognizes that they could have all been better friends in their youth.