Both Verizon and AT&T are moving towards new 'share everything' plans which emphasize data and texts over voice. I'm on AT&T so I'm not exactly familiar with VZ's plans, but I am certain that it will be significantly more expensive than you are paying now. VZ doesn't even seem to be offering tiered voice and text plans anymore - it's either unlimited or the one 700 minute plan.
Basically, from what I can tell, you'd pay a minimum of $50/month for 1GB of account data access. (All devices could draw from this pool). Adding your smart phone would cost $40/month, and each basic phone would cost $30/month. Every phone would have unlimited text and talk. Still, you're looking at $180/month before taxes and fees. I doubt you'll get any kind of business discount for a single line.
Honestly though, I'd go into a store or call to make sure, because your usage doesn't seem to be a good fit for their new plans. My experience is that the salespeople are actually willing to make sure you get the best deal.
Edit: Even on AT&T with their tiered plans you wouldn't make out any better. You're looking at $90 for 1400 shared minutes. $10/month for each additional line. $20-30 for your data plan, and $30 for unlimited shared messaging. So ~$170 for no data pooling (or tethering) and no truly unlimited calls (although it's nearly, with unlimited mobile to mobile calling and free nights and weekends).
I guess because of that unlimited mobile to any mobile (bundled with the unlimited text plan) you could go with a 700 minute shared plan for $70, which might save you as much as $30/month over verizon, depending on what data package you choose.