Cavigni, Bertolino, Orsino, and Verezzi make up the boys' club of Udolpho. They're hot-tempered schemers who all seem to have a thing for Emily. Every one of them is dissatisfied with the lot they've been dealt in life, so they've turned to the Condittieri to get some extra loot. And it works for a while: who wouldn't want to live the easy life and rake in the dough?
Cavigni's got a mean sense of humor when it comes to making fun of Madame Cheron. Think Eddie Haskell on Leave it to Beaver: he's a little smarmy, but slick enough to get away with it. Poor Madame Cheron has no way of knowing that Cavigni's passionate compliments about "that face—that shape—that air" are nothing more than hot air.
Bertolini seems like he might be the best of the bunch, but that's not saying too much. He's got some "strong passions" and "unbounded extravagance" working against him, but at least he's generous and brave (2.3.2). Then again, he's no peach when he gets drunk with Verezzi.
Verezzi's a major schemer. He scares the bejeebies out of Em one night when he's feeling drunk and amorous, chasing her through the halls of Udolpho. Dude, you're not in kindergarten anymore. Radcliffe tells us "he revolted against all subordination," which gives us a pretty good idea of his contentious relationships with the other guys in the castle (2.3.1). Verezzi has some major beef with Orsino, who keeps beating him in cards.
Orsino has to go and wreck it all for them, though. He's Montoni's favorite, but he's also the most selfish and proud. Really, dude, did you have to kill that nobleman and bring the wrath of the government down upon Udolpho? Orsino may be the "chief favorite" of Montoni, but he's also got plenty of "pride, revenge, and avarice" (2.3.183). Watch out for him in a dark alley.