1) I score all merchant and trader of the opposing players
2) I choose one type, for example merchant, and i score all merchant of the opposing players
3) i score a mix of merchant and trader depending on number have the opposing players in her crew (example player one 2 merchant, player two 1 trader and player three 2 trader, i score 5 VP)
Number 3 is correct. 1VP per card that your opponents have hired.
I read #3 as "For each opposing player, you choose either Merchant or Trader and score 1VP per card of the chosen type in that opponent's crew. You may choose a different type (Merchant or Trader) for each opponent."
But I read Shem's response as "Count the number of Merchants and Traders in all opponents' crews. Score that many VP." Which I'd interpret as #1 above.
I thought the correct ruling would be #1, but now I'm a little confused...