Regarding the Pentoshi, I can actually explain why they aren’t so big on the Seven Worship–they might be related to the Andals, but they seem to have been pretty thoroughly Valyrianized, so to speak, as opposed to the proudly cosmopolitan Braavosi. Of course, this does beg the question where the custom of sacrificing their Princes came from…

That doesn’t seem to have been the case that much. Indeed, we’re told in the World of Ice and Fire that “the first Pentoshi were merchants, traders, seafarers, and farmers, with few of high birth among them; perhaps this reason they were less protective of their Valyrian blood.”

So yes, they are Valyrianized, but much less so than the Lyseni or Volantenes.