A question regarding biome overlap and NPC Happiness

[Terra B Welch]

Just wondering, if a NPC is housed in their prefered biome but it's overlapped by the hallow, does it still count as their biome for happiness?

Mainly asking in the case of hallowed desert/hallowed snow biomes. I made a desert house with the dye trader, arms dealer and nurse living in it, I wanted to make the nurse happy so I made the desert into a hallowed desert, are the arms dealer and dye trader still satisfied with the biome despite the fact it's hallowed? It's technically still a desert so that's why I was wondering.

 

[Pizzarugi]

No, Corruption/Crimson or Hallow overlaps will invalidate most biomes for NPCs. I moved my dye trader to the desert, but when hardmode started and eventually took over the spot, they no longer talk about how much they like being in the desert despite it still being a desert albeit with Hallowed properties.

 

[The Terramere]

The regular biome pylon will work in hallow, you could also use hallow pylon. Though in forest or cavern you must have it pure