(i) Juliet and Kate were walking towards the Losties' camp when they encountered Smokey... they used the sonic fence to stop him. My question: which side of the fence was he on? The inside of the camp or the outside...? Since Juliet and Kate needed to travel outside, wouldn't it make sense that they shut Smokey on the inside...?;

(ii) the flashes that Juliet saw... was Smokey communicating with Juliet? Giving her some information...? I think that Smokey can give as well as take information from people;

(iii) could the flashes also be related to Desmond's future seeing..? "Flashes before your eyes" sprung to mind immediately when I saw this...

I think they were walking back to the Others camp during this episode. Because Kate wanted to see what was still there, so they blocked it outside the Others camp, so it is still lose on the island.

I think it was taking information. Like you know the saying " Take a picture it lasts longer"? I think that's what Smokey was doing.

(i) Juliet and Kate were walking towards the Losties' camp when they encountered Smokey... they used the sonic fence to stop him. My question: which side of the fence was he on? The inside of the camp or the outside...? Since Juliet and Kate needed to travel outside, wouldn't it make sense that they shut Smokey on the inside...?;

If you think about it, it really doesn't matter what side of the fence they were on. When it's off, it's off and Smokey can go on either side. They didn't "shut it out/in" anything. They just used the sonic fence to make Smokey back off.

(ii) the flashes that Juliet saw... was Smokey communicating with Juliet? Giving her some information...? I think that Smokey can give as well as take information from people;

With this, you will just have to wait. TPTB will come to that eventually. That's a mystery...not a problem. It can be bugging you becuase it supposed to bug you.

(iii) could the flashes also be related to Desmond's future seeing..? "Flashes before your eyes" sprung to mind immediately when I saw this...
The title surely seems so. But i think the "Flashes before your eyes" has something to do with his life....actually "flasing" before his eyes.