It depends on their height over the counter and the 'throw' (AKA 'spot size') they give.

I think it depends on the size light fixture you are planning on having. For example, our island is going to be 75"x28" approximately and we are using 3 lights. But our lights are very narrow (I think about 3") and the light is more focused rather than wide. Not knowing what you are planning on using, I would probably try to have a pendant over the shorter side of the L and probably 3 lights over the long side. But again, it depends on the pendant size and light spread.

I think slender buffet lamps on each end would look great! I say no pendant lighting..that way it will look unique and not like a residential kitchen. I love these metal finish lampswith matching metal shade from Restoration Hardware..offered in 4 finishes...

It depends what they are made of? Glass, Metal or something else? If they are a heavier looking light you definitely should go with something smaller.