Do I need some kind of isolation between 3051 and 4067.
yes you can use an optocoupler as one way of doing it.
I tried simple npn driven form micro giving ground out to 4067 and pulled 4067 inputs high with 10K to 12 volts. And kept the micro out pulled high with 10K to 5 volts.
You need a combination of npn and pnp transistors with few resistors to do the job for each pin.
Regards
Mahmood