Hello everyone,
I just noticed one interesting thing about noble residences. Now when noble residence is possible to trade it is completely useless to upgrade then to the level 4. The problem is that it gives you just +10 settlers capacity, but it cost you 1000 gc (marble is not important). For such prices it is possible to buy 2 noble residences (current prices on Newfoundland) and it seems that the prices are going just down so later maybe it would be to buy even 3 for 1000gc. Anyway with 2 noble residences upgraded to level 3 it gives you +100 settlers capacity. The most important thing is that it doesn't cost player any building licence. I just managed to replace in such way all my normal licenced noble residences with the traded ones and it didn't cost me even a gem. So in my opinion somewhere in game it is possible to get noble residences very easily, that the prices in coins are such low (maybe just price in gems are too low .. hard to say). I leave deep analysis to you ;-)