After the factory reset skip the google account creation, then Settings - Apps - CloudAgent - Disable app. Finally, go to Settings - Accounts and create a new google account.
Yes, lower screen resolution requires less power because there is less pixels and cpu/gpu will have do less work per unit. I am not a gamer but the FPS question is hard to answer because it depends on game (or better say on game engine).
There is no best screen resolution unless you specify the screen size. In that case pixel density (pixels per inch) matters not the resolution :) Remember you may set the text/item size in modern OS such as Windows 10 so the resolution has no effect to the text size. For 15 inches screen size...
I assume the problem appeared with no change to OS or apps. I would recommend then to focus on background processes - i.e. I would perform scan with MSE, Avast etc. Do you have installed any antivirus?
There is a Lock switch on the left side of the SD card. Make sure the Lock switch is slid up (unlock position). You will not be able to modify or delete the contents on the memory card if it is locked...
A few years ago I was able to recover data from SD card with http://www.cgsecurity.org/wiki/TestDisk free tool (don't get it wrong - it is a file recovering tool - not a test tool :) ). However, it depends whether your SD card has been really corrupted or just files ave been regularly deleted by...