First thing wrong I see is you don't have (or didn't mention having) any source of UVB. Dragons need daily exposure to UVB rays from bulbs that produce them (for your tank size, the UVB florescent tubes will be your only option). UVB allows their bodies to produce Vitamin D3 which in turn is needed to utilize ingested calcium. Without one or more of these things, your dragon can't thrive.
Replace the CHE with UVB florescent tubes. There is no practical use of Ceramic Heat emitters in bearded dragon tanks. They need bright and warm spot/flood lights providing both heat and light to simulate the sun. Though CHE's produces heat for them, dragons don't recognize it as a 'heat source'. Dragons instinctively go for the brightest and highest area they can reach to get warm, even if this spot isn't the warmest part of their enclosure.
Next thing, not sure the coroplast (plastic sign material you mentioned) is a good substrate choice, it may be too slippery....and if not in a single section and sealed, fluids can leak around the edges and seams...though as substrate choices go, its a pretty good one. If it seems your dragon is having a hard time moving about on it, cover with paper towel. If she moves fine, then don't worry about it.
However, if the cage has a plastic smell...I would remove it. The heat from the lamps may induce it to release toxic chemicals...but I have heard this stuff used in Chameleon cages and I don't think there was any toxicity issues, but I rather err on the side of caution.
Back to heat...CHE and flexwatt won't be necessary at all, if you have a good spotlight heat source. If nighttime temperatures in the room the cage is in drops below 65F at night, then supplemental heat at night may be necessary, either from the CHE or flexwatt on a thermostat. You don't' want nighttime temps to be over 75F though. Between 70-75F is good temperature to aim for for night time heat.
Just to make sure, the 100F hot side temp, is this air temperature or surface temperature of the basking spot? If Air temp, its too high, should be lowered to about 90F. The surface temperature of the basking spot should fall between 100-120F. To measure surface temperature, use either a temp gun (best method) or a digital thermometer with probe which can be lain directly ontop of the basking spot.
For the female, can you give more detail on her behavior? Never adjusted since you bought her doesn't tell much...is she eating at all? Is she hiding all the time? Does she bask or hang out on the cool side of the cage all the time or in her hide? What are you offering her for food? How often? Do you handle her at all? If so, how often?
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PHLdyPayne