Fireworks can be seen from the Esplanade, from in front of La Brea Bakery in DtD, from in front of the Jazz Kitchen Express in DtD, from the lawn by the exit to DtD (on the ESPN Zone side -- just follow the sidewalk around to the end of DtD, there will be a grassy area on the side of the sidewalk -- you'll see other people waiting for the fireworks).
I would assume that all pool privileges are reserved for guests of the DLR hotels. Other posters may have more info. You could always call/email the PPH to see what they say.