Can I use this analog switch for CAN bus signals?
I have never used J1708 but according to wikipedia, J1708 is not a CAN bus. It is apparently a UART-based bus using RS-485 transceivers. Meaning you can't connect it to a CAN transceiver in the first place. 

J1939 on the other hand is a standardized CAN-bus protocol, using CAN.

So, no you cannot use analog switches or dip-switches etc because you don't have two CAN buses. Instead connect the J1708 through a RS-485 to the UART peripheral of the MCU, completely separated from CAN.