Will this work ?
Should I keep them close to my heater ?

I put 4 cups inside of one of those jars...and I use a very fine cloth like organza over the opening with a rubber band to secure, so no gnats can get in there... I put the lid over the cloth that way I can open to breath/ get some air. Yes by the heater and move to a sunny window during the day... I keep moving mine around..those in there are doing much better than all others. It was a savior. 

As long as you don't fill it with little green men you should be fine.  I like Grasa's idea.  Also the one closest to the camera is desperate for more light.  You'll have to watch the temps to be sure you don't cook them.  I use a $10 Walmart weather sensor.  It has a base unit that senses temp and humidity and temp at the remote.  Either would probably fit in there.

Yes,  first day, put with the paper facing the light, on the first few days,  so it gives a bit of shade to acclimate the new leaves. If you can monitor and give a couple of hours and increase the time is better. if you put by the window for a long time, make sure the lid is not too tight or they will cook in there. that is why I use the cloth over it .

here is mine.
http://figs4funforum.websitetoolbox.com/post/In-hide-from-gnats-6212674

Grasa,
I followed your link to look at your nice photos and noticed a lot of condensation on the jar's walls inside. 
How do you determine when it is too wet or too dry inside?

when condensation forms on one side I open the lid, leaving the fabric only and spin the bottle to get warmth from the other side, I have not watered mine in almost 3 weeks now. Condensation form only when the plastic is not breathable, I am trying not to use them. But in ziplock bags, I open a bit and blow my CO2 into it and close again.  3 out of 4 are great, one grew leaves first and never sent out roots, so that is a fail, but I will try again. 

Nice work Figs4Life...you are on your way...best of luck.

My new mini greenhouse




And my smallest cutting 1/2

Will these be safe if I keep the out of my green house?

As long as you can check on them every few hours, I say try it.  Several of mine adjusted without any issues while some still needed humidity.