That looks like a pretty balanced set of positions. I know that I only have 1 designated PF, and I play him as my SF. You could place either a Center or Small Forward at your PF position, depending on the style of team you want to form.
You can definitely stand to sell off or fire a few guys, it will save you a bit on wages too. Remember that the suggested positions are just that: suggested, so you are free to play your players elsewhere if your gameplan or training suits them.