1. Overall, the design looks pretty good. The fact that you added the number of available points and how to earn them is great. The only thing I'd probably add would be a catchy header or something that pointed out that is the Points Store; you know, to make it look different than the rest of the pages in FP.
2. Yes and no. While some of them seem useful and could be interesting for most people, some of them are intended for a reduced group of people (like the ultraviolet tester). I'd love to see plenty of more gadgets there, from the cheapest ones to the reasonable ones, and perhaps, in the future, electronics like cellphones, tablets, etc. Although those would cost too many points.
3. Yes. I myself have earned a few from competitions and shopping. While the points given while shopping are quite low, I have to admit the FP staff is very generous when it comes to giving away points. One remarkable thing is your "Guess the box" contest - that is the best feature I've seen a page offer in exchange of points. My only suggestion would be to give a little more points when shopping.
4. Yep. Once you get to add more items to the exchange shop, adding categories would be helpful and would let you keep things organized. Also, maybe, you could add 2 different categories for the items that are already there - "Available" for the ones you can redeem, and "Still not available" for the ones you don't have enough points for or that are out of stock. Finally, somewhere stating that you do give points to people here in the forum or in the Facebook page.
Just my 2 cents. Thank you!