but Vailians are nothing but extra-tanned Italians
There's nothing coherent about Vailia or the worldbuilding of Deadfire for that matter.
Deadfire is based on the Caribbean and the Golden Age of piracy. During this time period the 4 great powers that had the strongest colonial empires were: Spain, Portugal, France and England. In that order. Italy didn't have an independent participation on the colonization of the New World because most of it was already under the Spanish Crown, from Naples and Sicily to Milan. Another good chunk was under the Pope, and the rest were semi-independent city-states like Venice or small kingdoms like Parma. Going solely by this fact it's completely impossible for the vailians to be seen as an accurate representation of Italians because their most prominent contribution to colonization was cultural, as we can see in the many barroque buildings that exist today in the New World.
Then there's the completely anachronistic inclusion of the "Trade Company" style of colonization that was NEVER practised neither by Spaniards or Italians. It's a completely Dutch and British invent, and only for India and the Orient, that's why it was called the "East India Company". Both the British and Dutch company had very little presence in the New World. But it's easy to see why it was included: is the closest equivalent to the stereotypical vision of evil colonialism, because the Company was mostly concerned with profit. If they had to represent the Spanish or Portuguese empire they would have to portray them constructing buildings, churches, and even universities and you can't have that in your "historically accurate" game because that might go against The Narrative
™. Obsidian can claim to be history nerds all they want, but Deadfire is nothing more than poorly made fanfiction in regard to real history inspiration.