An active x-over is more efficient and requires power, hence being active.
passive is not powered and less efficeint. Passive can only take so much power, active don't think it matters.

a LMS is a loudpeaker management system like DBX driverack or soundweb.
Controls crossover, EQ, delay, dynamics and possibly more.
That soundweb is designed to run whole building audio so can alter amps eq etc from one place.
A noraml LMS just would run one sound system of a mulitple of speakers.
http://www.bss.co.uk/includes/produc...rchived_flag=0

The soundweb will work but is excessive fro your requirements, i think anyway.

Ultracurve is a digital EQ.
Apex is limiter.

If you want you can ring me and go over it, would be easier.

U will need laptop for soundweb.