I wouldn't really call Pinkie's family aristocratic. Her family are artisans/craftsponies, well known artisans, but still artisans. Going back to it I would say that her family is upper-middle class, they are somewhat famous (amongst those who truly are into rock gardens) and working on the palace's garden's was a once and a life-time honor. I was drawing on the idea of artisans as being outside of the noble circle of honor, and your question made me run back and double check to see if I hadn't got my facts mixed up on Edo-Japan. Pinkie's family is apart of the Samurai-Equestria's version of the artisan or craftsman class. Even though many pony nobles take part in the arts as leisure activates, to make money by producing an art or craft is generally looked down on as beneath them and dishonorable. They may make their own paintings or small rock gardens, but to actually paint portraits or travel around and design people's rock gardens for pay would be demeaning.
Pinkie not fitting in with the nobles and bureaucrats was a concept that was developed during the weekend. I realized that I had an idea of Pinkie's relationship with her mentor, but not with her peers at the palace.
As I have never really worked in a bureaucratic organization, I just asked some relatives to relate their experiences and generated some concepts from there. In a bureaucracy at least nominal based on merit, jumps due to supposed favoritism are general frowned upon as in the case with Celestia and Pinkie. Especially if this isn't do to any true measureable ability, Celestia sees the kind, incorruptible, and straightforward nature of Pinkie and perhaps, even in twisted mirror of Samurai-Equestria, she sees one of the ponies who would be able to weld one of the elements of harmony. However, the power of "heart" cannot be tested and is generally thought of as worthless by more practical types. It will not increase revenue, nor will it dazzle ponies with references to classical literary texts and allusions that sophisticated palace ponies like.
Thus I figured they would probably be somewhat hostile to Pinkie Pie and then I rolled with it using the first season finale as a guide and also how Pinkie wanted to prove herself as competent in "Baby Cakes". But now that you've pointed out, blanket reactions in a group are bad, some of the palace ponies are probably hostile, some not. However, I believe that most would have trouble taking Pinkie Pie seriously. She hasn't been educated like a true top of the elite and is an outsider of mediocre skill levels.
As for if Pinkie had adjusted to high society, I can actually see that if given enough time. However, I imagine that Pinkie Pie would have only have been in the palace training for 1-3 years, rather then raised up from a early age like canon Twilight in Canterlot. As a side note, I was going to add a line that she had already got her party cutie mark some time ago, but then I realized I didn't know if Samurai-Equestria had cutie marks. After all, there is less magic and a theme that is developing with these characters is that who they truly are (their passions, loves and wants) are often hidden behind a mask. A outward honest appraisal of who they are really wouldn't work. Besides they wear clothes anyway. Maybe the cutie marks are just extremely private? "Hey baby, what's your mark?" being a common sleazy pick up line.
Pinkie hasn't been educated to be apart of high society. In human years she would be around 17-20 when she was first noticed by Celestia and entered the palace. Also Pinkie isn't just moving into a common noble society, but the highest of high. This is a society a large step removed from Fancy's noble family and would view Fancy as trite, these are ponies who actually manage to see and speak with the immortal alicorns themselves. They do tend to get a bit snobby and look down on outsiders.
She would probably find their ways boring, and, after attempts to be their friends and get along with them and being looked down on as borish, generally keep away from them. Still, Pinkie being Pinkie, she probably has a few acquaintances, perhaps fellow Inspectors or Inspectors in training who she is on speaking terms with. No true blue friends or buddies. More like cordial co-workers at best, nice, pleasant, but they aren't inviting you to any social gatherings.
In my own experience in university and watching different people from different classes moving into a university of an other dominate class (like say lower to higher class) three things generally can happen. The first is that they do their best to act like everyone around them and convert. The second is that they don't socialize and keep to themselves, generally with a vibrant life away from the university's dominate culture. The third that can happen is that person becomes not quite one class or another, they may be too high class for the lower class they left at home, at the same time, they are too low class for the high class people around them at the university. This can be a sense of empowerment, with the person being able to move through both classes with ease, but can also serve as a point of entrapment, not being ever able to truly be apart of either.
I like the idea of a mix of one and three, with Pinkie having a few groups of drinking/partying/theater going buddies from the merchant, artisan and lower noble circles in the entertainment district of the capital, while at the same time picking up some of the habits and higher ideas of the palace. Such as her faith in the system and a mission to right wrongs. If Pinkie is already somewhat shunned, dismissed, or just not taken seriously, she probably wouldn't bother hiding her travels to the lower quarters. Either that or perhaps it's a open secret or rumor. Of course, Palace security being what it is, it's not like she can take her
stallion or mare friends home. Whatever the reasons, Celestia, even Samurai-Equestria Celestia, isn't the type to honestly care and that's the main pony Pinkie cares about. While the security of the palace is tight, it isn't an Imperial City style shut down.
The parties in Samurai-Equestria that Pinkie Pie likes involve drinking in more humble/common/middle class bars, restaurants, tea houses and the like. Silly, loud and crude jokes and wild (but ultimately harmless) abandon, and a good time for everyone, with little thought of your reputation or standing. The other entertainment that is available and Pinkie likes is theater, kabuki-ish dramas, comedies, puppets, acrobats, and of course, magic shows.
Because every type of Equestria has magic shows.
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