I noticed a strange thing about Demolitionist that I do not see mentioned on wiki.

Practically on my world I created immediately a good number of houses with all requirements needed to accommodate an NPC.

The first NPC that arrived was the Nurse. Then I found many bombs but Demolitionist never came. He arrived just immediately Merchant came, when I finally got the 50 silver coin needed for him.

Is this behavior correct? Is there and order in NPC appearance in addition to the minimum requirements for each one?