I wrote a bit about my thoughts regarding BPD vs. APD earlier and why I suspect the latter, but HPD is also entirely possible (again, not enough information to be certain).
As a slight aside, a thing about these cluster B disorders is that there is a lot of overlap between all four and it's often extremely difficult to correctly diagnose without in-depth in-person analysis that often involves actually not interviewing the patient but those closest to them (mainly due to possible manipulation by the patient). Due to this major overlap, it's actually possible that Isabella might not fit into any of the diagnoses in the DSM-sense but rather has "a little bit from everything" and these people aren't actually that uncommon who have 1-3 traits from each of different cluster B disorders. This is actually the worse than having any specific, but correctly diagnosed cluster B disorder because, for example, if you have BPD you get prescribed anti-depressants, mood stabilizers, and likely sent to CBT, but if the professional dealing with you cannot pinpoint the underlying causes and be certain in which direction to take the treatment to, the mistreatment rate is extremely high as it is easy to approach the treatment from an incorrect angle. All in all, cluster B is a pain to deal with and how the professionals don't really want to deal with it has a certain truth to it.