for lights you can use 8 or so par cans w/ different colors. and 8 or so more pars chasing to the beat of the music behind the bands and out to the crowd. you can use two moving heads to spot light soloists and scan the crowd. you don't want too amazing of a light show because then you will take attention away from the band.
as for audio...you said that you could borrow from yamaha...i don't know their products but if you email me i can talk to you about some other manufacturers that would work perfect - dj_borris@hotmail.com - so let me know.
the question that was asked about drum mics...i dbout you would need any if its only a ***** of 200 but if its outside then you will because peoople will wander around for 3 hours. so you would need a mixer with many mic inputs with preamps. if your indoors, how big is the room your in? For trussing you should use adj's crank stand truss...the ones that go up 15 feet. get two of those...one for infront of the band and one for behind. if you don't get good enough light you could also add two more tripods off the the left and right of the crowd with par cans on those. also remember that each band is going to ask for something different. if ya can talk to the bands ahead of time and get info on how many mics they want and ather such things. DO NOT ask how loud they want it...because i can answer that...they all want it LOUD!!!! as do students. hope this helps
DJ Borris