I think your range requirements is probably going to be the killer, not the licence!
The Baofengs might do half a mile, maybe even less in built up areas - you might get 20 miles hilltop to hilltop with line of sight!
For you and the family you only really need maybe one to two frequencies. 5 miles range is going to sink the project I suspect.
If we’re being honest, you’ve already been playing with them - how did they work - range wise?