st pierre en faucigny
As it makes sense and since I don't see a hint of otherwise or ambiguities in the rules, I'd say:
AMATERATSU: only the doubles the points on the Prestige Point tokens that look like fans you take as bonus, not the points printed on the buildings, not the points printed on the specialists
NAKASTU: one way only. (there's even the converse specialist raijin: two boats for one gold)
Thanks for your enthusiasm, Seb
And thanks to pg for having given the good answers before me !