Would I be endangering my outdoor in-ground trees if I were to give them their winter pruning now, possibly still 3+ weeks away from 1st frost?  My worry is that the trees would invest a lot of energy into pushing out new green growth that would promptly get frozen before paying dividends.  Would that cause enough additional stress on the trees that it would dramatically affect their odds of surviving winter?  (mulch will be their only winter protection)

Wow, interesting questions!! Watchibg this thread for the answers.

Open cuts will allow the freeze to enter the plant and do more harm, since they have not hardened off yet. 

Perhaps stop watering to slow down new growth and allow it to start sheding its leaves in prep for winter. Maybe only water when the current new growth starts to wilt.

I did a huge prune on three trees. Leaving only main trunk as a experiment to see the way it fruits. Seen some really big fig trees in my area with huge main trunk and only new growth from this,season. I waxed the ends with toilet ring wax. It is nice & thick.

Thanks for the replies, everybody.

I would just wait, but I like to keep things simple.

Hi,
For me, it all depends on the temperature that you have outside.
If the temps no longer go over 12°c and 5°c at night or go lower, the trees won't start growing again.
I've started some chopping on some branches that were done with figs for this year and that were in the walkway or already growing in the neighbor's garden.
It is my take on this, that you should air the wounds for a week or two before installing the protections, or you may get mold.

Nevertheless, here, I wouldn't install protections too soon as rodents are still moving around seeking hides for the winter ... and you would be making a nice setup for them...
So I would wait until the frost has come and the beasts have settled a bit more.
Last year, a neighbor used a large (4m*4m/ 14'*14') plastic sheet to kill weeds. When he removed the sheet, that land had become rodent's central highway field.
You could see their roads at the top of the dirt as the plastic provided them some shelter ... So not a good move IMHO.

You are in Zone6, so now you could cut how you want, let the wounds air, and protect the trees before the first frosts.