I don't think camera shake helps with fireworks at all, at least not ones that I like. I've only shot them once, used one camera with a tripod and another camera hand-held, trying to use somewhat faster shutter speeds. There was only one picture I took from the hand-held set that I liked (1/6 sec, f4, 50mm).
Which lens you'd want to use (telephoto or wide angle) depends on site conditions. Normally if you are close to where they are being set off wide angle is good. I made the mistake of using a wide angle to photograph fireworks being set off a long way from me - it was too late to change lenses or cameras on the tripod by the time I realized my mistake. This was as close-up as it went (24mm), I would have liked to have had something around 30-50 for a focal length under these conditions. This one was taken at 5 seconds, f8.
You'll need a long shutter speed to get multiple fireworks usually, and exposure is a bit hit-or-miss for me (quickly take one, check the LCD, make changes as appropriate).