Who I have the same questioned this topic

My wife just upgraded from a 4S to a 6S, and she is keeping the 4S as a Wi-fi only.  Yesterday she spoke with a Verizon rep who had her go through the steps to switch her phone.  Her 6S is now listed on my account page (it was her 4S before she spoke with the rep).  However, her 4S keeps getting text notifications, and her 6S isn't.

If she turns off iMessage and Send as SMS on her 4S, will this take care of it?  Any setting on her 6S that might need to be changed?  Is there anything else she should do on her 4S to make sure she doesn't get any calls, etc.?

Thanks!