if you had this system, what would you do to make it sound the best you can

Less is more in alot of cases. The Panamax is a pos unless for some reason they got better. The cheapest thing to do is the plug everything  direct to the wall.  Lose the equalizer.  Now adjust your sound field by placement  diffusion  and absorption.  Make sure your speakers are level as well as level to each other.ake sure they are exactly  equal distance  from the wall behind them and on either side. Make sure the toe in is exactly  the same. When that is done have a listen  and see what you have. After that is done repost and you can get help from there. Go get the free part and the basic part first. 

if you're using stock power cords that's the first problem get rid of all of them and upgrade them to OCC single crystal power cords and same with your interconnects and speaker wire, OCC single crystal has been proven to be the best wire for audio for over 50 years, there's many good manufacturers harmonic technology, acoustic zen, Zenvfino, and especially Neotech they make rectangular OCC single crystal wire which is even better than the round OCC single crystal wire.

if you're using stock power cords that's the first problem get rid of all of them and upgrade them to OCC single crystal power cords and same with your interconnects and speaker wire, OCC single crystal has been proven to be the best wire for audio for over 50 years, there's many good manufacturers harmonic technology, acoustic zen, Zenvfino, and especially Neotech they make rectangular OCC single crystal wire which is even better than the round OCC single crystal wire. Also putting the Townshend podiums underneath your speakers will be the biggest improvement you could ever do they isolate vibration down to three Hertz and they get rid of almost all room problems, The improvement was as if I had upgraded all my electronics to much more expensive gear.

Here are some easy things

Walk around the room.  Listen for certain frequencies changing volumes.  If you hear nulls or peaks, sound treatment.

If your system has been as is for a while, take all the interconnects and speaker wire apart and clean with DeOxit or Stabillant 22.

Isolate speakers from floor.  I used springs but my speakers have a big footprint.

Any old equipment in 20 to 30 yr range should be checked.

Those are low cost.  Another quick one is the ADD POWR company.  Most expensive one is $4000.  It will just open up the music, make it clearer and has a 30 day audition.. Turn it on and play music.  In 20 minutes, you will hear what it does.  Turn it off to double check.  Turn it back on, etc.  Have fun.

Thank you all for your suggestions and comments.  That helps me make some decisions on how to improve the system.

the system electronics are in a closet system designed for the pieces I have.

the room is challenging as it is 12x18, open with 24 foot at peak vaulted ceilings. I will checkout the suggestions and make changes.