Been here, done this. I tried this with 3 plants all about the size you mention or larger. The most successful one was the one I dug, transplanted into a large container and grew off for almost 8 months before planting. I planted a couple directly and they didn't do as well (one died). By the time I planted the potted one, it had great roots nearly filling the pot and it has done exceedingly well.
I'm sure trees do grow roots after dormancy, but not sufficiently to establish a tree like a fig I can assure you. (and I had significant roots on both of the ones I tried directly) the one I potted had few roots, but had a football sized root mass when I potted it.
Best of Luck on it.
~Chills