Everything seems exactly right. The cool side should be never higher than 75f, and 70 is OK. Where did you learn all this? A book, or maybe Facebook? Iguana keeping is not at all intuitive.
You can find lots more facts at: http://www.anapsid.org/pdf/icfs.pdf
Her tank is plenty big for her size at this time.
Does she like to hang out in the warmest spot?
Where does she spend most of her time?
Would you mind putting in a water bowl big enough for her to climb into, even though it makes you change the water 1 or 2 times/day? Also provide her usual water container that she can't poop in.
Total lights out begins an iguana's sleep cycle. The TV will delay it until it goes off. We don't really know how less than 12 hours of lights off affects them. In my experience 9 to 10 hours is fine. I think they catch up during the day. But my word is not the gospel here. So we practice 12 hours as a precaution.
Her position in the midst of the family's daily activities is the second best place of all. The very best is on one side of the activities where she can watch them but is shielded on one side by a wall. A good precaution is to provide her with a hide box that she can get her entire body into. A straight plywood upside-down v-shaped hide is the simplest and is effective at letting her escape from any stresses. She will feel far, far away in there. It should not be too roomy. It should be in the cool side of the tank.
with your report of her input and output, it seems like she should be growing. Now that she's alone, she may just need to recover from the stress of her prior cage-mate. Give her 6 more weeks to acclimate to her new sights, sounds, and smells. If she doesn't shed by then, she will need to see a vet for a fecal exam and a blood test.
Drench her food in water when you feed it to her.
We all say Welcome! to a new and meticulous iguana caregiver.