My husband is a USA employee who is working in Germany.
I work for a German company in Germany. 
We both are non-EU citizens.
We have a rental house in Germany.
I have given birth to my baby. I am currently outside Europe along with my baby (for few months) and my husband is in Germany.
My husband might have to return to USA forever. Since I am also not staying in Germany right now, he may terminate the rental house contract and vacate the house. 
So,Can I fill "change of address" form and give my address outside Germany?
Am I eligible for Elterngeld if we leave Germany (have no house in Germany) but I still remain on Elternzeit ? 

If you are not a resident or deregister then you would loose.