Can I have both a mouse and the tablet connected to... (by 2 users)

Yes, If you have a PS/2 mouse or support for a PS/2 mouse on your motherboard, both the tablet and the PS/2 mouse can be connected at the same time. If you have a serial mouse, you may have to manage the devices on your machine so that all devices that require a COMM port can coexist. The serial tablet needs an available serial port with reserved resources. This means that it can not share a COMM port address or interrupt (IRQ) with any other devices on your machine.
NOTE: USB model tablets will not interfere with a serial, PS2 or USB mouse.