Yes, that is a good range, how about light?

the gh is on a covered porch with S and W exposure. Its not very direct light right now, but very bright

I am not sure that you can avoid dormancy without having light at least to the same hours as spring or summer.  I kept my lights on 24/7 and my trees never went dormant.  I did not use grow lights

keeping lights on pass 14-16hours is a waste of money. plants start to slow down chlorophyll production around that range. plants reverse processes at night and take in O2 while putting out CO2.

Same thing goes for us. We have active hours and we have sleep hours (Circadian Rhythm)
24/7 daylight without at least 7 hour rest, I think that fig tree would start preforming sluggish.
As for those temp. yes your figs will keep their leaves through winter. As long as those temps don't fluctuate too much. 

Even in Brazil, high plateau where the temperatures are on the 70-80s all the time, the fig trees need rest. They drop their leaves and go dormant a while, then, start growing again. It is in their nature.

I should explain what I actually did, I turned on the lights at night as heaters, the daylight plus the night lights equalled 24/7  the daylight was medium/low level light through a window.  The trees never lost leaves.  The main differences I saw were the the leaves developed, and, stayed much smaller and the color was a very dark green.  The extra growing time helped in that those trees all were one season ahead in height and number of leaves.

I don't know what the negative impact is or will be, I do believe that you cannot fool Mother Nature, but the question is,  is the fact that a fig tree drops leaves and goes dormant a self defensive rest requirement or a compromise to the seasons (Mother Nature)?

Thanks for sharing.

Best,
Tam

My experience is that in colder climates dormancy is mainly initilated by the cooler temperatures.
In warmer, mediterranean climates it seems like dormancy is started of by the shorter days.
I'm in the south of Turkey right now on vacation and the temps are still in the high 70's at day and around 60° at night and the figs are starting to go dormant. Some smaller ones are already without any leaves.

Picture from yesterday:

Hi Christian nice tree.