Fed:
You asked a couple of questions in the previous post that have not been addressed. For starters, NO, you do NOT put an EQ or a dynamics controller (like a compressor) on an Aux Send, and then "mix it in".
You patch that type of processing directly into the signal path of a subgroup or main ouput section. Leave the Aux sends for mixing-in special effects (reverb/delay, etc) or to the monitors. EQ is definitely an"either/or" situation. Either it is in the signal path or not.
And truthfully, you should be able to get things going without a fancy EQ.
The channel EQ on those Mackies is limited but functional. You can use the "Sweep"control on the midband EQ to "notch out" resonances and feedback nodes, by lowering the gain on the mid control and then "sweeping" the "Hz" control for that band. Be careful with adding some old "black box" EQ to your signal path. Some of the stuff that schools tend to buy can do more harm than good...