I'm not sure why you think a blacklight will simulate a sunrise/sunset....I'd have to disagree. I fail to see any reason for using a blacklight, but I also don't necessarily see that it would hurt if used during daytime (but no lights at night as chameleons can see the full spectrum)
ACTINIC lighting is for corals b/c at those levels underwater, the "redder" parts of the spectrum don't make it. ABOVE ground, we use 6500K (NOT 10000K) bulbs. If you are not familiar with how "color temp" works, you may want to look it up, but in general for non-aquatics you do need the red parts of the spectrum (also why most grow lights are more reddish/pinkish hued).
I highly doubt that your reef-theory will carry over to the terrestrial (well, technically arboreal) setup in this case.
EDIT: Chameleons are PREY animals and that means they hide harm/reactions very well. Since this is your first chameleon, it is going to be quite difficult just spotting regular reactions in him, let alone introducing an unknown stimuli and attempting to gauge his reactions based on it. You won't have anything to base it on, imho.
SUMMARY of things you need/want:
UVB Bulb - many use 5.0 Reptisun; I prefer tube lamps for even dispersion, others use CFLs and have a focused spot...up to you really
HEAT/BASKING bulb - standard incandescent bulb in a dome works fine. Most use 60W, adjust based on your ambient temps
NIGHT HEAT - don't need unless your ambient night temps are below 60F. If so, use a CERAMIC heater (NO LIGHT) as chams can see red lights... (many "reptile" night products claim reptiles can't see red spectrum for nighttime vieweing bulbs, this is NOT true for chams)
If you intend to just have a basic large plant with a little bit of supplemental stuff, the 2x T8 fixture will suffice. If you plan to plant the setup heavily you will probably need more light. But if you are aiming for what most people have on here, then the 2x will prob be good.
Waterfalls are generally a bad idea and chams do not drink standing water (must have misting system). They drink water off leaves as it rains. However, this does not mean you can't have a waterfall...but unless you are making one with proper filtration and water changes/etc, I would not recommend one. As a first setup, I would further not recommend one as water features increase the complexity of the setup far more than they initially seem to.
As someone else said about 4' UVB costs....I personally use the 2' UVB bulbs. Have you considered 2 sets of 2x2' rather than 1 set of 2x4' bulbs for this reason.
Lastly, DRAINAGE!!! Due to the amount you are watering your plants WILL GET FLOODED. The "standard" approach to this is to setup a drainage table a few inches raised. Also, I would *HIGHLY* recommend using a more aerated soil (I use Fox Farms Ocean Soil "blue bag" from hydroponics shops or you can create your own by mixing potting soil with a fair volume of PERLITE, COCO CHIPS, or similar). This will prevent your soil from being too wet and drowning your plants. You can try to avoid the drainage layer by using larger pots and filling the bottom of the pots with 1-2" gravel or hydroton but you still have the issue of where the drained water is going to go....
To save some cash on the silicone, Lowe's carries GE SILICONE I - Windows and Doors and this has been time-tested by many many froggers over at dendroboards with success. GE II silicone also works but is not as recommended for closed setups due to some anti-mold ingredients; however seeing as this is an open air setup it should work fine (I personally have used GE II for a few years now with no problems).