Thanks for the reply Scott. So, you're saying if I replaced my Joey 3 with a Joey 4 I can install all my streaming apps and watch them on the TV the Joey 4 is attached to with no Plus needed. That's good. You're also saying that (for now) the wireless Joeys can't accommodate any apps. Perhaps that will change in the future.Each Joey 4 is its own streaming box. The apps you install on one will not automatically show up on another Hopper 4 in your house.
For question 2 yes she would need a Joey 4 on each TV to have the Android TV apps on them.
Is a tech visit absolutely necessary to replace my Joey 3 with a Joey 4?