I can't speak too much of the cavs unit but I've heard many people have and like them..
But I would look into some other equipment as far as you power amp goes
Stay away from VOCOPRO ...I won't get into the quality aspect of their equipment because thats subjective ..some people like them..MOST do not.
BUT THE COST OF THEIR EQUIPMENT can not be argued .....
Try a PEAVEY PV1500 AMP fpr the same price you will be getting a more powerful better sounding better built unit. EVEN BEHRINGER offers a better power amp AT A LOWER COST.
The Vocopor unit for your back up is $549+/- ...Look at some of the
other topics on this site and you will find much better suggested euipment that is lower cost - higher quality with more features ...
JVC/RSQ units whether single tray or triple tray units ... for DJ'ing and KJ'ing ..Look at the NUMARK 25CDG .
Speakers are a good choice other options would be
YAMAHAS115V - $329/EA
PEAVEY SP5 - $350/EA
Good luck