I have several potted figs that I put in an unheated basement. 
They were dormant when I brought them into the basement.
The basement is mostly dark, but there is some light trickling in.

It is mid-february and they are starting to leaf out / some have established breba.
I am in Zone 6 in Pennsylvania.

What are my best options at this point?

I can move them to a more lighted area of my basement, water them, hope for the best?

I could move them to an attached garage....

I could wait and bring them out in April/March and prune off the new green growth?

Are there any other options?

IMO, the most critical variable is warmth, not light.  

You have to slow down the growth process or you will end up with weak growth that will not easily survive a transition outdoors.  Permitting then pruning weak growth will just waste the plant's resources.  The breba may be toast in any case, as they are likely to drop due to stress.  

The basement is not a good idea -- it's probably too warm to slow growth but too dark to support healthy leaves and stems.

The attached garage is probably your best bet.  Mine stays generally in the 40's, sometimes down to mid 30s, which seems more than warm enough.  I'd prefer it to be 25-40 F.  But given that you already have growth, I'd try to keep the plants above freezing.

You may still have problems keeping the garage cool enough during warm periods in early spring.  So you may have to start a shuffle in late March / April.  

I would start acclimation now, put them out if above freezing, take them back in below freezing (not a frost), for 2 weeks. They should go dormant again, and if they do, put them out till 25F if lower, bring them in. But first they must become dormant again.

Does anybody know what's the coldest temps the plant can take before the figs are endangered, the figs already forming and/or fig buds?  I've got the same problem. 

I agree with all Joe wrote. Great advise. I built a dormancy building for my figs but for years I kept over 400 fig trees in my garage with virtually zero problems.
I do not worry about anything until temp drops below 20F.
I also agree that it is temperature not light that brings figs out of dormancy.
A basement is a terrible place for figs unless you set up a grow room.
I'd move them to the garage if there is a good light source.

Oh yeah -- forget about the brebas as they will do whatever they are going to do now no matter what you do.
If they were mine I'd pluck the brebas off and let the trees concentrate on new growth.
My experience is the brebas may hang in and do nothing, possibly they'll ripen or more likely one day you'll walk by them and sneeze and they'll all fall off.
My policy is unless brebas are doing exactly what I think they should be doing I get rid of them as long as we are talking about carica figs.
For ones like Filiacciano Bianco, etc. things are obviously different.
Anyway -- good luck.

Time for the fig shuffle!! free exercise!! I will do up to 30 until april 15th watch the weather forecast daily!!If you leave them in the basement bring them out when when danger of last last frost has passed and put them in the shade and let them acclimate slowly to the sun.