If anyone has to do it then it should be the house owner, but I would not bother. If he needs to put an address for the immigration form then book a place print it out and then cancel it later.
not so easy regarding Cambodiabno border open. You can be stopped at the border in Laos and questioned and asked to provide reason for re-entry, finances etc.
the amount initially deposited can be the minimum the bank requires. The 800,000 needs to be there from the date the immigration office requires. Not the same thing.