Combining DC power input from multiple erratic sources (solar / wind turbine)
The big unknown here is that you have two MPPT chargers, one for the solar and one for the wind. These are fairly complicated devices with a microprocessor inside making decisions, both with regard to finding the maximum power point of the input and assessing the state of charge of the battery on the output.
The good news is that they should themselves act as diodes and not allow backfeed to the generators.
As you say, the most natural approach is to connect both sets of chargers to the battery and let the voltage find its own level. If power out &gt; power in then this voltage will be determined by the battery state of charge. On the other hand, if power in &gt; power out the battery will be charging but you can't necessarily say how charged it currently is.
All I can say is to check the manuals for the two chargers to see if they have any guidance on connecting to a battery with another source of charging. If they say not to do this, then don't. If they say how to do this, you're fine. If they say nothing (the most likely outcome), you have to decide whether you feel lucky - it will probably work fine but nothing is guaranteed any more.