Straight Talk and Verizon are both CDMA carriers/service providers. So in theory it should work.
However, you would have to have unlocked phones for one, and you would also need to know if the Straight Talk would work in your area and accept those phones.
If the phones aren't unlocked, then there is no way to switch. So fix that issue first. If they are unlocked, or you can get Verizon to unlock them (as that is who has to do it) then I would check with Straight Talk directly and see if those phones will work. Only they can tell you for sure.