Background info...I have been keeping chameleons for over 20 years...the first one I had was a Senegal and I have had a few of them over the years.
You said...""Rzilla light with a UV bulb"...."The bulb is a winding tube"...Brad is right...if its a compact I would replace it with a Repti-sun 5.0 linear/tube light
You said..."Basking temp is 70 degrees F"...as someone already said, this is too cool of a basking temperature. You can use a regular household incandescent bulb (in a hood) of a wattage that brings the temperature up to the low to mid 80's. Try putting your hand at the closest point that the chameleon can get to the bulb...if you don't have to take your hand away, then it won't likely burn the chameleon. Appropriate basking temperature plays a part in digestion and might be part of the problem with the feces, if its not within the right range.
You said..."We also have a layer of hydroballs underneath a layer of bedding and moss"...I do not recommend using substrate with any arboreal chameleons. Its too easy to end up with an impacted chameleon.
You said..."We dust the crickets with calcium supplements and the crickets are fed an orange "brick" of sorts"...IMHO both of these things need to be improved. I'll discuss supplements and gutloading/feeding crickets further down.
Watering a Senegal is important. I have found that if you just mist the cage, they won't drink enough. I recommend that you mist the chameleon gently or dribble water on the tip of its nose until it starts to drink. Be careful when its drinking that you don't spray hard or into its mouth or drip on the nose to rapidly so that the chameleon aspirates the water.
You said that the Fecal Description was..."bright yellow/dark orange"...there should be a dark brown "sausage-like" piece (the feces) and a white piece (the urates) and there should be a bit of clearish jelly-like stuff.
You said..."Its grasp was weak when I picked it up"...this concerns me a bit...but it might be nothing.
How long is the chameleon (total length or length snout to vent)? I am assuming its WC? Depending on its size when you got it, it could have mated in the wild or along the way before it got to you....but as Brad said, they don't ususally produce infertile clutches in captivity. If it is gravid, then that could be why its sitting on the floor of the cage. If its grip is truly weak it could have to do with that or possibly even calcium issues.
If its not just a matter of making a few husbandry changes and the issues still persist, then you should take it to the vets.
Supplements and lighting:
Exposure to UVB (that does not pass through glass or plastic) allows the chameleon to produce D3 which allows it to use the calcium in its system. The best source of UVB is, of course, the sun. If your chameleon is kept indoors then the UVB fluorescent tube light is what will provide the UVB.
Most of the insects we use as feeders have a poor ratio of calcium to phosphorous, so dusting the insects before feeding them to your chameleon with a phos.-free calcium powder helps to make up for this.
To ensure that a chameleon gets its vitamins, I dust twice a month with a vitamin powder with a beta carotene source of vitamin A. Beta carotene will not build up in the system...the body converts what it needs. However, there is controversy as to whether all chameleons can convert beta carotene to vitamin A or not, so some people give a small amount of preformed vitamin A once in a while to ensure that the chameleon gets some. Preformed vitamin A does build up in the system though. Excess preformed vitamin A can prevent the D3 from doing its job and lead to MBD.
When the chameleon gets no direct sunlight, then dusting twice a month with a phos.-free calcium/D3 powder is advised. D3 from supplements can also build up in the chameleon's system...so don't overdo it.
Gutloading the insects and feeding them a nutritious diet is also recommended. Crickets may be fed an assortment of greens (dandelion, kale, collards, endive, escarole, mustard greens, etc.) and veggies (carrots, sweet potato, sweet red pepper, squash, zucchini, etc.)
Calcium, phos., D3 and vitamin A are the four main players in bone health and need to be in balance. When trying to attain this balance, you need to look at the supplements and what is fed to the insects and the chameleon.
I hope this helps!