For once i am going to post a sensilbe responce in an eminence thread. I know, i know what is the world coming to, but if NG can do it, I guess i could as well.
I would shy away from the same crossover points for the diff woofers, unless you are cotjones, then go for it, but like its been said you will most likely run into some cancelation. i would skip the 10's, and just run 6's, or vice versa. Heck run more 6's to make up for loosing the 10's. or vice versa. same goes for the horns, and tweets, try crossing them over to play diff freq's. i think i remember you saying that your horns play up to 9k? so cross them over just below that, and cross tweets just above the horn cross, or find a midddle ground.
Power issue, you said you plan on running a separate power source @16 volt for the hk 4000's, so that is taken care of. for those amps you plan for the "front stage" a 200amp alt should do fine imo as long as you provide sufficient time to recharge batts after a good long time playing them at full tilt.
kevin