Please be as specific as possible when letting us know what is missing or incorrect. For example, say "this game's trophy difficulty should be 8/10", with a link to a website corroborating this difficulty estimate (if possible), not "this game's trophy difficulty is wrong".
The All Legends Pack immediately unlocks all current Legends and every Legend we add in the future. Everything in the “Legends” tab in the in-game store would be yours to have. Forever. Note that this doesn't unlock Crossovers.