As I mentioned, only a few countries are left with the opportunity to show an income proof from their embassies. You are probably from a place where your embassies give you any. You have your 800K in the bank already, so no need for any income proof! You probably would not get one anyway. There used to be any more, but that has stopped. I asked the immigration about when I should meet up to apply for a non-immigrant-O visa and they told me 20 days before your 60 day visa exemption run out. I guess a lease contract will be good nut cannot answer if you need a copy of the blue book and a copy of the owners ID card. I think you should as a lease is like a rental contract. I would ask someone at the immigration office about details, just in case I am wrong about your case. There might be a few differences from one office to the next. Mine is Nakhon Ratchasima, Korat, and they are a pleasure to deal with.
PS. The reason I was at the immigration office was that I reported that I was back in the country at my adress. This should be done within 48 hrs of arrival. I used the opportunity to ask them them when to apply for a non-O, thats it. People that stay at hotels will automatically be reported arrived, so no problem. But as a private renter of house/apartment, you have to go and report yourself. Don't forget or you might get a fine. When it comes to you people that have to deposit 800K, I am not the right person to ask about just that.