Do I need TVS with Optocoupler relay
I am afraid the relay you've chosen is not an opto coupler. If its a mechanical relay it will have a coil with an inductance and it can't change it's current instantly, the flyback diode provides a path for the current when the coil is switched off. Otherwise, a voltage spike will occur causing arcing on switch contacts .
TVS diodes are used between the supply/signal and Ground for transients. What you should be looking out for are flyback diodes. perhaps schottky diodes would be ideal for this application