Have you tried using Billshrink.com? You can put in your current phones, plans, prices, etc., and what you want in a new plan, and it will run comparisons with all the major vendors.
ETA: I doubt you can beat $200 for that many phones and data. Just a quick glance at Verizon shows they charge $40/mo per smart phone, and $30/mo for basic phones. 4 GB of shared data would be another $70/mo. That's a quick $280/mo right there.
AT&T is $35/mo for each smart phone, if you buy 6GB of shared data for $90/mo, plus $30/mo for basic phones. $285/mo. And since AT&T are a bunch of bastards, they also charge you $20/mo for each device if you want to enable 4G hotspot functionality.
Sprint will let you get 5 lines with unlimited data on their network, unlimited text, and 1500 shared minutes (free mobile to mobile) for $220. Their website won't let you add a 6th line.
Good luck. Maybe look at prepaid lines as well.