I have a few misc questions for you all.

1) At what point do you consider a cutting ready to handle regular room humidity? ie if it can handle X amount of hours out without wilting, it's ready...?

2) At what point do you feed your cuttings, and what is your method of choice? What I have handy is 'BioBizz Fish Mix liquid fertilizer', 'Jobes organic fruit and citrus granules'  

3) Thus far I have NO GNATS (knock on wood)...I am potting up some of my cuttings into 1 gallon containers and using pro mix HP. Would you recommend I isolate these up-potted plants away from my gnat-free cuttings? I did not use pro mix HP for my cuttings in cups.

Thanks.

1) At what point do you consider a cutting ready to handle regular room humidity? ie if it can handle X amount of hours out without wilting, it's ready...?

You slowly wean it to room humidity. I have a small bag on mine i poke a small hole, then gradually increase the size of the hole.

2) At what point do you feed your cuttings, and what is your method of choice? What I have handy is 'BioBizz Fish Mix liquid fertilizer', 'Jobes organic fruit and citrus granules'  

When there are sufficient roots.

3) Thus far I have NO GNATS (knock on wood)...I am potting up some of my cuttings into 1 gallon containers and using pro mix HP. Would you recommend I isolate these up-potted plants away from my gnat-free cuttings? I did not use pro mix HP for my cuttings in cups.

I dont see any reason to separate them. Over watering kills more cuttings than anything

I can only comment on (1).  It really depends on the cultivar.

All my Peter's Honey did fine coming out of the bin,  never had a single one wilt.  They all have a 2 to 5 leaves when i took them out.
My LSU Tigers all had problems coming out of the bin.  The first one stayed out 56 hours before it started showing signs of stess.  Putting it back in the bin helped it.  I had to take it in and out a few times to get it hardened.  The other LSU tigers showed the same issues.

Both of my Texas blue Giants died while trying to harden them.  One did okay for several days, so I potted it up, then it started wilting.  Put the pot in the bin, but it never recovered.  The other one died before I even got it out of the cup. (Well, I'm assuming there goners, but I'm still holding out a sliver of hope for them.  I'm gonna pull them up and see if they still have any roots at all).

basically, if it has lots of good roots, you can start trying to harden it off.  You can put it in a vented bin that has a lower humidity and keep lowering the humidity every few days (venting more).  Or take it out one day and put it back a day.  

I think one of my problems was too high humidity in my bin..   I think it actually started raining inside it.

Thanks for the comments given so far.
I have mine in large clear bins. The lid isn't sealed so there is always a small amount of air circulating. I take the cover off once a day in the evenings and have been leaving it off for longer intervals. I have one container with some of my 'older' cuttings and the lid has been off for 2 hours with no sign of any leaves getting wilty (maybe longer but I haven't tested beyond 2 hours). If they can handle an evening without the lid, are they ready? Or should I continue to harden them off more?

Some of these older cuttings were starved for nutrients. They were ready for food and I didn't realize it, hence my question about feeding them. I gave the cranky looking ones a watering with a small amount of the liquid fish fertilizer in it and the newer leaves the are putting off look happier. When I plant them up into the next size, can I follow the directions of my Jobes organic fruit fertilizer? I think it's 1/2 cup per gallon. I can obviously cut this back. I am also adding bone meal.

I don’t have any problems acclimating to room humidity. Most of mine usually have more roots than leaves as I pluck off any vigorous buds while developing in paper towel land. 

I fertilize regularly using ¼ teaspoon Miracle Grow to a quart of water. I’ve tried this on plants that are pretty dry with no apparent side effects. Your mileage may vary.