Unfortunately at this point in time we have not been informed of any detail surrounding plans and “how 's” regarding restorations. We just know that people are still at work on this situation, but sadly nothing that can serve as a proper answer to your questions 
Just to be clear: this is not because there are no plans at all, it’s just that any related information has not been shared with us so far… reason why we can not really comment on anything related to this topic.
The only part we have been informed on with clarity is regarding the bug that lead to the disappearance of items in the first place.
Said bug has been located and fixed some time ago (a couple of weeks ago if memory serves, I can’t double check right now, apologies 
), which basically means that guild banks are safe to be used again since then. Using guild banks should also have no impact on any future plan to complete the resolution of the situation as a whole.
That’s correct, in cases such as this one we can pretty much only act as a communication “link” between players and the teams involved in investigating and fixing the problem.
Rest assured that we’ll keep doing our best to get you any relevant information as soon as we get them 