Single cavity sliding door which can span 2.8 meters?
If you want to close it off, why not extend the wall from 930mm to 1330mm, and then that'll allow you to put double sliders in there?
Moving in this week! What to do first when you move in???
I think it'd be cheaper to upgrade your carpet to a stain resistant one, rather then scotch guarding the whole carpet.
How to know fall in land and how much would it cost extra ?
Hard to tell, best bet is to talk to a builder. Fall is expensive in building and 2m is significant.700mm isn't. Probably only a few (2-4)thousand depending on other site…