You’ve mentioned the FM are a holy order, what do you think of the idea that they may be evil or in cahoots with the WW or cold magic on account of being a death cult?

I think those opinions are entirely mistaken. In many, many cosmologies, death is seen as a part of the natural order that should be respected as any other. Assuming that a religious society that venerates the god of death to be evil is the kind of thinking that led Indiana Jones and the Temple of Doom to depict Kali (who represents both destruction and creation, and is a destroyer of evil forces) as an demon who had corrupted the worshipers of Shiva (who, in addition to being a benevolent god, is also known as the Destroyer). 

GRRM has gone to some lengths to let us know what the Faceless Men are about. They have their own history and legacy, which doesn’t tie back to the White Walkers at all. Assuming everything in Planetos ties back to either the White Walkers or to the dragons is basically arguing that GRRM engaged in bad world-building, because it means the world doesn’t exist outside of the spotlight.