Short sales take the longest because the seller is making a case that they have a hardship and are unable to pay the difference between the sales price and what they owe for the property. That evaluation can take time, especially if there's more than one lender involved, Mortgage insurers,etc AND whether the package presented to the lender is complete in its original submission.
If you are looking at buying a home that is short sale, it's important that your buyer's agent check out the following: the seller has a legitimate hardship, How many loans need to be approved in the short sale, and the experience of the listing agent in negotiating a short sale. Knowing those factors will give you better insight into how long the approval process might take, and if it might be approved at all.
'Foreclosures' is a legal process by which a lender takes possession of a home when a buyer defaults on their contractual obligation of paying their mortgage.Ii assume you are talking about bank owned properties (sometimes also referred to as 'corporate owned' properties). Those properties were sold at auction, no investor buyer bought it, so ownership reverted back to the bank who is now selling it as an REO property. I don't believe that purchasing an REO is any longer than buying directly from a seller who has equity in their home.