Honestly bro, I've never had as severe of an accident as what you sustained, but I have and still do put my body through some pretty rigorous things and I would highly recommend starting yoga. I had a snowboarding accident years ago that put me out for a long time. My back never really healed right and has caused me pain ever since. I am also a competitive MMA athlete and I've torn MCL's, ACL's, etc. and yoga has helped me out exponentially. It has helped my core strength, balance, flexibility, and made my body feel like it is healed.
As far as the cycle, I would hold off. When you feel you are 100%, you still have more work to do, IMO. I would do lots of yoga for a long time. That's just me.