Is casting a "pox" on one's house associated with the Greek Orthodox
or Eastern Orthodox church?

I doubt that this is tied to any particular church beliefs. The phrase
"a pox (or plague) on your house" was a common one in Medieval and
Renaissance times.

Shakespeare's character Mercutio says "A plague o' both your houses"
in "Romeo and Juliet," and there is no sign that Mercutio is a member
of any specific church body.

Saying that you wish a pox on somebody or some group was originally a
way of wishing ill. "Pox" is short for "smallpox;" therefore, you're
wishing bad things will come somebody's way. The phrase has no
religious meaning.

Kriswrite

I'm sure these religions do not recognize such silly superstition any
more than would Catholicism or main-stream Protestantism.