A:AnswerYes It Can. Just Make Sure That It Shared Under The Computer That You Are Sharing On Your Network. At That Point You Can Browse To The Drive Under Windows Explorer By Using Your Network Option Area.
A:AnswerBy box I assume you mean the box the product came in. That is not necessary. Taking this through security would be no different than taking a laptop with a HD (or even an SSD) through security.
A:AnswerYou Can Definitely Have More Than One (1) External HD' Depending On How Many USB Ports U Have On Your PC. You Can Also Ad A USB Hub To One Of Your USB Ports To Add More USB Ports. As Far As Auto BackUp To Another Portable. You Will Have To Have A BackUp Program That Supports "Mirroring", Which Would Automatically RollOver To Another Drive Should One Of Your Portables Become Full.
Hope This Helps.