You can connect multiple dc generators in parallel to a battery and they will all contribute as long as the emf of each is above battery volts, Series connection is not useful.
The main reason not to use lots of small wind turbines is that you are duplicating expensive items such as propellers and towers and generally one decent size one costs less and performs better but sometimes 2 or 3 sited for various wind directions can be better on poor sites.
For wind and hydro, combining several sources makes perfect sense.
Don't worry about regulators unless the battery is fully charged, the battery will drag all sources down to the same voltage and current from each will be determined by their open circuit voltage, impedance and more probably the mechanical energy available to drive each. Hydro will be a steady contributor and wind will only contribute when there is enough energy in the wind, it may be the biggest contributor on a windy day.
Flux