Best to avoid all of these. If you have to buy an actively managed fund, buy the fund with no sales charges at all. 12b-1 fees are really remarkable. These are yearly charges that the fund takes out of your money so that it can market itself. You don't want to be paying those at all.
Turnover measures how long a fund is holding onto the stocks it buys.
The longer a company holds onto a stock, and the less trading it does between different stocks, the lower the turnover will be. A mutual fund that has an established track record is less important than you would think. Past performance really isn't an indication of future results. However, a fund that dramatically underperforms the market is more likely to keep doing so. You don't know what that fund is going to do.