Is it ok to cold smoke steak before freezing?
No issues, as long as you control the temperature and remain outside the danger zone.  In other words, can you cold smoke below 40F (4.5C)?

Time in the danger zone is cumulative.  Freezing does not re-set the clock.  If you can't stay out of the danger zone during the smoke step, I would smoke, sous vide, then freeze.  This is probably a more common approach.  You can then re-therm the steak directly from frozen when you are ready to eat.

As an aside, 6 hours seems like a long time to sous vide a rib-eye...even from frozen.