I know sometimes help may sound condensing, but if there was anyone I would ever trust on any website or forum when it comes to understanding audio acoustics it would be M5.
Not to chastise you in anyway, I have never in my life seen so many drivers in an install at any competition I have ever been in whole only driving two 15" subs.
Best in show is awarded for a visual appearance not any type of physical audio accomplishment.
You have some nice equipment to achieve what you are after, but you have created an insane amount of anomalies that will physically never yield good results other than visually.
Everyone who has posted above has had nothing but the best intentions of helping. Nobody will ever "spoon feed" you information because history has taught mankind that's not how one learns the "how & why".
I wish you all the luck but, if I were you I would not have so many drivers to try to blend with only two 15" mtx subs. If it were six 15" subs maybe but what you are doing isn't working for a reason.