[Geekcop]

Welcome to Geekdom! To answer your question, a hard reset resets your phone to out of the box condition. If you have a custom ROM installed, it will not change this, but otherwise your phone is in the same condition it was when you got it. Clear storage does just that...it clears your storage of any files you have residing there. On that note, I'd suggest a clean up app (SK Tools or MemMaid) to keep junk files from accumulating and eating up storage.

As for your customization question, cant help too much