Q: iPhone 6 internet tethering on ATT - to what devices?

This is a pre-purchase question to figure out what's possible and what's not.

I currently use EasyTether on Android and am able to just plug USB direct from the phone into my MacBook and tether the internet service off of the phone.

Mobile Hotspot supposedly replaces this, and should, theoretically be able to be used by any device with password, seeking WiFi.

All with the permission of your carrier (mine is ATT) - and eating up your data plan.

Does ATT have any other tricks or hidden charges going on for using this?

We currently have 2 iPads on our plan as "extra lines" at $10/month each on ATT.  I'm guessing we could cut them off and just use the iPhone 6 data when needed?   We currently have a shared data 6GB/month plan and use less than 1GB/mo. over 2 phones and 2 iPads... so there's lots of extra room for increased usage levels.

Is it possible to hard wire the connection to an iPad or MacBook and NOT use mobile hotspot?  Let me know if i have any of this other stuff wrong...