I thought that a caste could only influence someone towards a specific aspect, not a class? Why would being a Jadeblood influence towards Sylph if only one of the Virgos we've seen is a Sylph?

That’s a good question! It’s actually arguable that they may be influenced to an extent by both Pre and Post Scratch Trolls’ Classes, but I wouldn’t be able to confirm the pre-scratch thing. That being said, the Class Stereotypes are intrinsically bound to the Classes as well, like how the WP team how all Ceruleans are influenced by the Pirate stereotype, it pushes them to behave like an Outlaw, fitting under the Thief Class, or the highly dangerous Highblood Cult that makes Purples heavily prone to Destruction. All Olives we’ve seen so far, too, have Outlaw motifs, like Nepeta, fitting as a Rogue. The Rustbloods’ forceful Servitude falls under the whole Maidenhood motif in a bit of an oblique way. It’s noticeable, but a little bit less direct than the Aspect influence.