Keep in mind... a "mixed reef" is the absolutely toughest to keep and manage. Mainly because nothing in the tank is entirely happy due to everything having to be somewhere in-between what all the different types of coral really prefer. Someone in the tank is always sacrificing their "preferred" environment.
Softies unhappy because water is to clean for SPS
SPS unhappy because water is to dirty for Softies
LPS unhappy because to much flow for Acros
Acros unhappy because light is to low to keep Softies from bleaching
Softies bleaching because light is to high to keep Acros happy.
It can be done by making use of tank depth for different par values, but it's always a trade-off on all aspects of the tank.
Just depends how much of a "mixed reef" you're really trying to keep.
Much easier to keep closer types together like Softie/LPS, or LPS/SPS, or SPS/Acro
Now, with that in mind you can ignore all that and just go with what works... hell, our RedSea 350XL has some Acros, Zoas, and Mushrooms all on the top level doing just fine, and it's not a super complex tank setup.
Why? Because my wife likes it that way... and it's working... and it keeps her interested in the hobby.