Breba figs come from leave nodes of previous wood, while main crop figs are from the current, new wood.
Ripening time of a given zone depends on temperature, sun light, fertilization, soil, etc.. The length of time to ripening, even on the same tree for each fig can be different.
You raise a good question on the late forming figlets as to whether one should remove them, knowing that they are not going to mature when cold weather hits. I think it all depends on if your tree is in ground or not. Potted fig trees can be taken inside a green house to lengthen the growing time, so some of the immature figs can have the chance to ripen. In ground trees are not able to do that, though I have seen some push the ripening process by removing all the leaves out before their time to hasten the ripening process. Some even apply oil on the eyes to do that. I do not know how effective these techniques work, though.