My goal, when I was a DJ (1975-82), was to get in and out of the gig as quickly as possible. This was where you made your money. So simplicty is what to shot for.
We'll just talk about the Klipsch
1. If you plan on working small rooms, then use the KP-250 with KP-480 would be the way to go. All you will need is a large power amp driver the whole thing (min 375wpch@8 ohms). I would run the rig in mono so you could run the KP-250s on one side and the KP-480 on the other. This way you'll get some control of the low end. NO-ONE will hear the stereo image at a party, beleive me! Later you can add in the extra stuff for stereo.
2. If it's Big Gigs then use the LaScalas with the subs. Keep in mind the LaScala is a good long-throw design and may be a problem when trying to fill the sides of a hall. Again use one amp at the start and work up.
Sound like you're starting out. Get a good pro power amp(s) (crown,qsc,crest,ev...). Get a good comb rack for every thing (GenzBenz). and a VAN!!
EQ's for the Klipsch I found to be UNnecessary in small to mid gigs. Alot of it is in the recorded material anyway. just set the level between the subs and mains and go nuts.