Your cage is only 24 go with that.
that Arcadia T5HO also puts out way more UV then a Reptisun 10.0, so that is plenty

.
I have also seen people do testing on Arcadias, and they were still producing enough UVB after a year, where as Reptisuns are toast after 6 months or so. I would still advise you replace the Arcadia every 6 months unless you have proper UVB tester (expensive). I wouldn't go that route unless you had more than 1 cham. With 1 it wont pay for itself IMO. However if you had a few bulbs going all the time, the 200 dollar tester would pay for itself in a year lol.
As to the other question about heat and basking. That is a yes and no.
T5ho Bulbs do produce alot of heat, and with enough of them you could use them for basking. However with the UVB and Grow light I would say it would help to raise the basking temp but not replace it. I have seen setups using only 6 T5HOs produce a 90 degree basking temp, so it can be done. However it would require way more wattage than just using your 2 bulbs and a low wattage basking bulb to raise the temp.
If you want less bulbs to deal with, another option would be a Mercury Vapor Bulb or a Metal Halide Bulb. they will produce both in 1 bulb.
IMO, best setup going to be expensive

.
Get a single T5HO ballast, 24 inch. A flood light halogen basking bulb, and a reptisun LED set. The grow LEDs have proven the merits doing just as well if not better for plant growth and way way less power. But way higher cost to get into the door.
On that option you have 2 ways to go. You could go with a Arcadia fixture and an LED fixture like this one
http://www.zoomed.com/db/products/E...7czoxOiIwIjtzOjg6IlNlYXJjaF95IjtzOjE6IjAiO30=
Or you could go with one of these that houses the LEDs and a T5ho
bulb.
http://www.zoomed.com/db/products/E...7czoxOiIwIjtzOjg6IlNlYXJjaF95IjtzOjE6IjAiO30=
The latter likely easier and preferable for you. Then just a basking bulb, and you are good.