Kathleen,
You are going to LOVE it! There is no posted schedule for the Boardwalk performers that I have ever been able to find, but you will surely find them out working the planks at night! The magicians, comics, jugglers, and other entertainers seem to be out there from Thursday to Saturday, but not Sunday to Wednesday. I could be wrong here, but I have never seen them on any day but the "long weekend" days.
As to the fireworks, yes, you can see the fireworks from Epcot's
IllumiNations show. Now because you are not in the park itself, you do lose some of the overall show, because you can't see the lighting effects on the pavilions of the World Showcase, or the pyrotechnic barge on the lagoon. But you can see the traditional fireworks soaring over the tree line.
The Atlantic Dance Hall/Jellyrolls side of the Boardwalk gives you the best vantage point for viewing, both for the angle and for not having the tree line in your way. However you can see them from pretty much all along the Boardwalk, so don't worry about it too much.
Have a magical vacation!