Amazon.com Ereader Independent Custom Font Installation Software

[Font]

I have been waiting some time when I asked the Amazon.com Ereader Developer's Corner forum section (https://www.mobileread.com/forums/forumdisplay.php?f=150) these questions and as I have not got any responses yet, I am putting them here because it is a more busier forum section:

Does the Amazon.com Ereader Independent Custom Font Installation Software (https://www.mobileread.com/forums/showthread.php?t=88004) have also impact on e-reader periodicals and the browser?

Is this the best and most popular Amazon.com Ereader Independent Custom Font Installation Software out there?

Please tell me what is the system for installing new fonts that are not in the Amazon.com Ereader Independent Custom Font Installation Software, it is not mentioned in the download sections?

In fact could anyone say what happens if all the fonts in the Amazon.com Ereader Independent Custom Font Installation Software have been deleted and a few new ones put instead, say a sans serif and serif regular and there are no italics or bolds?

Please tell me if corporate Amazon.com could in a firmware update stop and remove the Amazon.com Ereader Independent Custom Font Installation Software?

Could someone tell me the system for reversing from the Amazon.com Ereader Independent Custom Font Installation Software to the factory setting?