First of all, with lower back issues the trick is to rest... that simple. BUT, not to stagnate. so don't do deadlifts for a while!!! yet, do not sit around all day. walking is good for lower back and the following exercises:
Lying on the floor on a thin mat and holding your knees to your chest. lie like this for a minute or two (longer if you don't get bored) at one point you can gently roll your back around the floor in a circular motion and side to side.
hamstrings as noted above, but easy stretches, nothing to strong.
standing lift one leg and grab the knee, pulling to opposite side (mainly streches the glutes but this releses tension in lower back) can be done lying also.
sit on your calves with calves resting on your feet with your toes pointing behind and then strech forward with your upper body with arms reaching forward on the floor...
get on all fours and slowly arch the back while lifting head upwards at the same time then do the exact opposite causing your back to round and looking down with head...
repeat 5- 10 times. (Make sure no-one is behind you cos you look pretty funny and desperate when doing this)
I really would keep off the deads for a few weeks in your case, and also the squats for a week or so (go according to how you feel ultimatley) then once you are feeling stronger start with easy sets of hyper extensions for a week or two before attemting deads. Stiffleg deads in my opinion (I am really no expert on deads but...) are harder on the lower back then regular deads....
Meanwhile if it gives you no pain, working out the rest of the back might do some good and stop your back from stagnating...
Don't fuck with the lower back, I have a protuding disk between my lumbar and cervical region and it sucks... luckily working out carefully has really improved my condition to the point that I rarely even notice it.