What if you don’t use a cell phone but just a regular phone
are they able to listen to that as well?
Absolutely. They are under the rule of the FCC.
Yes!
And all land phones in government offices
It is more easy to listen to wired telephones and the listening device does not even have to touch the wires.
All communications including wired telephones, cell phones, email and all other internet communciations can be heard or read.
No communication, unless whispered by two people standing next to each other, is safe.