White dragons in Reign of Winter

[Piccolo]

One of my players is running a Druid, and so he'd like to get a white dragonhide breastplate.

I know that

Spoiler:

Logrivich the white dragon is in The Shackled Hut. Are there other white dragons in Reign of Winter that the party can kill?

Which books are they in? I have to know so that I can figure out how many dragons it will take to make a breastplate for said Druid.

[zimmerwald1915]

Take a look at Book 4, and watch all your troubles melt away . . .

[Lanathar]

Isn't there a dragon mentioned in the Book 3 Iobaria background. I think it is detailed as being very powerful

But Book 4 is the dragon book