UART and USB Serial at the Same Time

As far as I understand, the serial monitor function is actually UART communication from the Arduino to the computer with a USB conversion in between.

On devices that state they only have 1 set of UART ports, is the set of actual UART pins the same as the USB connection?

I have an MKR1000 and MKR1010 and I would like to have them communicate to each other using UART and also connect the Arduino IDE serial monitor to the MKR1000. Is this possible or can the device only handle one UART connection at a time?

You can use Software Serial on pretty much any pin -

Ended up figuring this out, the MKR series has two serial ports. One is only connected to the USB port with a serial to USB converter, and the other is only connected to hardware pins 13 and 14.