I’m also a newbie at large but I’ll try and answer your questions.
1.the first quest. I suppose you are talking about finding rehab properties and if they are not for sale by owners and you are having to go through a realtor to buy them the realtor would take care of all the steps that you’ll have to go through to purchase them.
2.again I suppose that you are talking about buying the property after it has already been to auction.And yes sometimes they continue to live there through the redemption period(the time that they some how can get the loan current).before they are evicted by the new owner (in this case you).If anybody can correct me and shed some light on this would be appreciated.But read and read some more from the posted forums in this site you would be able to gain some great knowledge.