I want to start by saying that I know that there isn't one distinct answer, as there is definitely a lot of variability between varieties and microclimate and what not. But in your experience, what temperatures have you found unlignified wood to be hardy to? 

My Hardy Chicago dies at 17 degrees or below.  I don't know what the lowest temp it can survive is.  I know dormant breba will survive 28 F.  So somewhere in there  :)

I just realized i said unlignified but i didn't specify actively growing, are those temps for actively growing wood? Thanks for your answer!

I would think anything actively growing would die if it froze. I'd say right at about 32 degrees. If the ground temp is warmer, and the air temp dips, you may be ok if it was a bit colder, but I would not want to risk it.

I set a bunch of young trees out early last year and they all froze. Most of them recovered, but they were set back at least a month.

The temperature I start to freak out at is 20F which I originally got from a good friend who also has a very large collection.
I have had years with virtually no damage. This year my trees went into a new building I put up last fall and there has been some damage.
I moved about 60 trees out of my new building and they are not going back in as I injured myself and live alone and my one helper is a fairly small woman.
So as we are seeing sub 20 degree weather I may learn a bit more about damage and which varieties are the most susceptible (I won't get a comprehensive peek though as the other 200+ trees in that building (I have another 150+ trees elsewhere) won't be exposed completely.
Anyway - I have seen real damage from the soft active growing bits when the temp has fallen down into the 20's. I usually throw an ag cloth over my figs if caught out in cold weather as you can get cloth's that will give you a 10 degree protection factor. Ag cloth's saved my bacon last fall as we were late finishing the building.

Good question, I have had non lignigfied dormant branches on trees in the garage during winter every year as well outside in the fall and similar to Pino's input I know they can handle upper to mid 20's. Yesterday I dug into the wood chip pile a bit on my in ground RdB  to see if anything was alive, there is a non lignified little green branch sticking up about 3" from the ground and a lignified one next to it, both were still firm and plump with fat terminal buds waiting for spring. The tree is covered with 6-8" of woodchip and we have seen multiple subzero nights this winter without much snow cover, the coldest were  around -10F. Who knows how cold it got next the ground under that chip but it had to be well below freezing.

I was checking my in ground figs this afternoon after a 21F freeze in the morning and it appears that most of the green tips on the branches were killed.

The weather had been warm and a 27F freeze about 10 days ago killed a few newly emerging fig leaves and brebas on my in ground trees in my open field,but my large in ground Southern Brown Turkey leaves behind my house weren't killed until the 21F freeze this morning.