No. That guy was korean. Looks nothing like him

Dont think so mate. I havent checked back, but what i remember hearing is;
"You think you're the first person that ever got conned?"
As if to say, 'hey this stuff happens all the time, get over it.'

I think Locke's Dad is the original Sawyer. Just like our Sawyer, it probably would have been an alias that he has used over several of his cons. Theres no point in arguing that his names Cooper and therefore he is not sawyer.. What conman would use a real name? I think 'Lockdown' makes it clear that he is/was a conman as he says how he did his "retirement con".

In 'The hunting party' Locke makes a big deal out of the fact that his names not Sawyer, but James, and asks why he chose it. I think that in the time he spent catching up with his dad, before the kidn(ey)apping, Locke probably heard or saw this name a couple of times.

Now, linking with other theories...

I recon theres a big-ish time lap between our most recent flashback (Helen leaving Locke etc) and the crash. This could possibly be backed up by the fact that the young guy bullying Locke about the walkabout, 'Randy' i think, was at a stage much after that as hes lost his hair, (and use of his legs), and he his seen when he is older (randy) having several cluckety cluck cluck days being Hurleys boss.
In this time, Locke's dad has thought of a new name, and established himself as Alvar Hanso and invests all of his long earned cash in certain projects such as the Dharma experiments. In the orientation video the hazy image of Hanso could be compared to Lockes Dad.

I believe that Lockes dad is likely to have some big part in the whole thing, perhaps as hanso. I think another big fish in the Dharma pond is Mr Paik. Both he and Hanso have a lot of power and would be necessary if the conspiracy theories turn out to be true.