If you're talking about a fixture for a UVB bulb, they do not get hot at all, maybe warm to the touch. The basking bulb could be a problem and would have to be place above the mesh not touching it. It's a good idea to have the basking light and UVB light separate. That way if they don't need the warmth and just want UVB they have it. Or if it's too warm under the UVB then they won't bask.
The fixture from walmart will not stand face down so i would recommend making a bracket to mount it to.You could do it like this https://www.chameleonforums.com/diy-double-light-fixture-39929/
Or put a bord going horizontaly the legnth of the cage and put legs on it to suspend it up and give you clearance for the bulb.