I definitely can't recreate a white screen. I've attached an image of what I see when I enable the SCLogin module in position-7, module ID 295:
The social login buttons do not appear to be showing in the SCLogin module, and I'm not sure why of that. However, if I edit the CBLogin module (ID 294) and in the Pretext field enter {JFBCLogin} all the buttons properly show there. That means the buttons still do work, but for some reason the SCLogin module isn't loading them. That could be an incorrect template override or something else, I'm not sure what.
I did disable the System - Cache plugin during my testing, but left Conservative caching on. Page Caching makes debugging things extremely difficult.
Please let me know if you are still having the same issue with the white screen, as I can't see that at all. Then we can decide how best to proceed.
Thanks,
Alex