MN, My experience with crappie is that they are not aggressive enough to compete with other fish. Mine survive but they have slow growth rates and are skinny. If I had to do it over, I would stock the less competitive fish(crappie, walleye, etc.) a couple of seasons before the other stock to let them get a head start. That's assuming you get a forage base well established. That's important.
At the least, you'll have a few good yrs. with the crappie before the dominant fish start taking over.
Got to be patient and not stock everything at once. I know its hard to wait though.