The reason for multiple charge controllers is because if you only use one, then you only collect
energy from the source with the highest voltage under load. So, for example, if it's really windy then you'd lose all the energy from the solar panels. One charge controller per source means that you collect all the energy from each of your sources.
Also, before you waste a lot of time and money on the wind turbine, I'd recommend you set up an anemometer at the same height and location as you plan to put the turbine and log wind speeds for a year to find out the true potential for that location. People tend to think it's windier than it actually is. Most turbines only produce their rated output power in 25 mph winds.
Also several studies have shown that turbines less than 20 feet in diameter never produce
enough energy to justify the cost of installation.
Small turbines put to the test
Solar panels are cheap these days, much better return on your investment, even if you have to use a lot of them.