detroit, the Jem Jr has a ILT1 trem, not a trs. Unfortunately, tts worse than a TRS. Also, there is no Fender Original Floyd Rose... its just Original FR.
Tany managed to fit a Gotoh licensed Floyd Rose into the ILT1 cavity and it has full range of motion. A Gotoh Licensed FR is one of the best Licensed FRs around, great quality, even better than the original FR. Check out places like internet music supply or www,universaljems.com to order a Gotoh FR, around $250 SGD with shipping.
If the Gotoh FR can fit, you can most prob use Schaller Licensed FR and Original FRs too... however, the Gotoh is the one with the best make/QC.
I am not sure if the legendary Ibanez Edge/Lo Pro will fit into the cavity. Even the Edge Pro too. Anyway, a brand new Ibanez Edge costs $275USD. So yeah.
Your best bet is to get a Gotoh, bang for buck and best quality, plus most likely to retrofit without routing.