Hi. I'm posting because I was in a similar situation to you this summer, although I only had 58 Grey tadpoles/froglets. To be perfectly honest, this number was more than I could comfortably handle, and I had to reduce pretty quickly by releasing the largest ones, which you will not be able to do until spring.
I can tell you that you are going to need a LOT more than two fruitfly cultures. I would start making more cultures right away; like maybe a couple dozen of them, and continue to make new ones at a steady rate. You may want to order a few more to start out with. You're also going to need pinhead crickets, which you will need to order in the thousands. I ordered mine from
Ghann's Cricket Farm. While they won't guarantee live arrival if the temps get below 25F, they will still ship. They ship from Augusta GA, which shouldn't be too bad for you, and you can increase the chance of live arrival by picking them up at the local Fed Ex hub, rather than waiting for home delivery. You will want to dust all of their food with alternating vitamin and Calcium/D3 supplements.
I hate to tell you this, but these frogs will eat you out of house and home. If you can collect a whole lot of termites, that should mitigate it somewhat.
With my babies (which admittedly were larger than yours) I found that 8 of them in one Kritter keeper was too many, once they were fully morphed, and I started moving them to ten gallon tanks as soon as their tails were completely gone.
This is a picture of the type of setup that I used to morph the tadpoles.
I put together the ten gallon setups along similar principles, with a gravel substrate covered in sheet moss (from Josh's Frogs), climbing branches collected locally, and cuttings of Pothos, which root into the gravel and start growing very rapidly. With this type of setup, I've found that I didn't need to clean it all that frequently, certainly not everyday, and I didn't have to move or handle the froglets to do it (in the big tanks). I basically just sprayed things down really well, and did partial water changes, which you can do with a turkey baster. I keep water over the entire gravel substrate, but with only a small section of the gravel shallow enough to go below the water level and provide a small pond. To keep fruitflies from escaping, I used flexible fiberglass insect screening of the type you can get in rolls at a hardware store. The Kritter keeper lids will snap on over them easily. For the ten gallons, I put the hook side of a strip of velcro all around the tank, which holds the mesh in place pretty well. This way, you don't have to leave the entire tank uncovered while you do things inside it. I then kept a standard screen tank lid over the mesh. I still have my remaining six frogs in a pair of ten gallon tanks set up in this fashion, though I'm in the process of getting an Exo Terra 18X18X24 set up for them.
When I was at my peak number, I had five tanks set up like this, with about a dozen froglets in each one.
I honestly can't imagine trying to do 137 Grey froglets, which is more than twice the number that I had. It felt like total insanity with only 58 of them, and this was during the summer, so I was able to release them as I felt that they were ready.
You might want to seriously consider trying to find a reputable dealer to take most of your froglets off your hands at some point. You also might want to try posting in the For Sale/Trade forum here, as I think there are frequently people around here who are interested in Greys.
You've really got your hands full, and I wish you the best of luck.