You want a light fixture that has a ceramic base that the bulb screws into is all. For the bulb, just use a regular household incandescent and don't waste your money on a specialized basking bulb. For the wattage of the bulb just make sure the basking spot hit the correct temperature. You might have to try different wattage bulbs to get the correct temperature. The basking temp can be found on the caresheets for the particular chameleon type that you are getting.
No, get a regular household incandescent like I stated above. That will be the bulb to use for basking. There is no need for the special basking bulbs. Just make sure your basking temp is the correct temp according to the caresheet.